Lung perfusion with protective solution relieves lung injury in corrections of Tetralogy of Fallot

Effects of pulmonary perfusion during cardiopulmonary bypass on lung functions after cardiac operation

BACKGROUND

Pulmonary artery perfusion during cardiopulmonary bypass (CPB) is a known but rarely used technique in adult cardiac surgery. In this study, we aimed to investigate biochemical and histopathological effects of pulmonary artery perfusion during CPB on lung functions.

METHODS

Between May 2014 and August 2014, all patients (n = 24) who gave informed consent for participating this study with inclusion criteria were included. Patients undergoing isolated coronary artery bypass grafting were sequentially randomized to conventional CPB (control group, n = 12) and conventional CPB with selective pulmonary artery perfusion (study group, n = 12). Lung functions were monitored using PF ratio, alveolar-arterial oxygen gradient, and lactate levels. A small sample tissue from the left lung was excised for histopathologic examination. Immunocytochemistry analysis was performed using anti-rabbit polyclonal vascular endothelial growth factor (VEGF), rabbit polyclonal inducible nitric oxide synthase (i-NOS), and BCL-2 antibodies.

RESULTS

Postoperative course of the patients were uneventful without any clinical outcome differences in terms of cardiopulmonary complications, ventilation time and hospital stay. Pulmonary perfusion group had significantly better oxygenation values after extubation and at postoperative 24-hour. Electron microscopy examinations revealed better preservation of the alveolar wall integrity with pulmonary perfusion. The intensity of VEGF, i-NOS, and BCL-2 antibody expressions in bronchial epithelial cells were more prominent in the pulmonary perfusion group.

CONCLUSIONS

Pulmonary artery perfusion during aortic cross-clamping provides better oxygenation and preservation of the wall alveolar integrity after coronary artery bypass grafting surgery. This technique can be used as a protective strategy to minimize CPB-induced lung injury in adult cardiac surgery.

Lung Protection Strategies during Cardiopulmonary Bypass Affect the Composition of Blood Electrolytes and Metabolites-A Randomized Controlled Trial

Cardiac surgery with cardiopulmonary bypass (CPB) causes an acute lung ischemia-reperfusion injury, which can develop to pulmonary dysfunction postoperatively. This sub-study of the Pulmonary Protection Trial aimed to elucidate changes in arterial blood gas analyses, inflammatory protein interleukin-6, and metabolites of 90 chronic obstructive pulmonary disease patients following two lung protective regimens of pulmonary artery perfusion with either hypothermic histidine-tryptophan-ketoglutarate (HTK) solution or normothermic oxygenated blood during CPB, compared to the standard CPB with no pulmonary perfusion. Blood was collected at six time points before, during, and up to 20 h post-CPB. Blood gas analysis, enzyme-linked immunosorbent assay, and nuclear magnetic resonance spectroscopy were used, and multivariate and univariate statistical analyses were performed. All patients had decreased gas exchange, augmented inflammation, and metabolite alteration during and after CPB. While no difference was observed between patients receiving oxygenated blood and standard CPB, patients receiving HTK solution had an excess of metabolites involved in energy production and detoxification of reactive oxygen species. Also, patients receiving HTK suffered a transient isotonic hyponatremia that resolved within 20 h post-CPB. Additional studies are needed to further elucidate how to diminish lung ischemia-reperfusion injury during CPB, and thereby, reduce the risk of developing severe postoperative pulmonary dysfunction.

Lung Protection Strategies during Cardiopulmonary Bypass Affect the Composition of Bronchoalveolar Fluid and Lung Tissue in Cardiac Surgery Patients

Pulmonary dysfunction is among the most frequent complications to cardiac surgeries. Exposure of blood to the cardiopulmonary bypass (CPB) circuit with subsequent lung ischemia-reperfusion leads to the production of inflammatory mediators and increases in microvascular permeability. The study aimed to elucidate histological, cellular, and metabolite changes following two lung protective regimens during CPB with Histidine-Tryptophan-Ketoglutarate (HTK) enriched or warm oxygenated blood pulmonary perfusion compared to standard regimen with no pulmonary perfusion. A total of 90 patients undergoing CPB were randomized to receiving HTK, oxygenated blood or standard regimen. Of these, bronchoalveolar lavage fluid (BALF) and lung tissue biopsies were obtained before and after CPB from 47 and 25 patients, respectively. Histopathological scores, BALF cell counts and metabolite screening were assessed. Multivariate and univariate analyses were performed. Profound histological, cellular, and metabolic changes were identified in all patients after CPB. Histological and cellular changes were similar in the three groups; however, some metabolite profiles were different in the HTK patients. While all patients presented an increase in inflammatory cells, metabolic acidosis, protease activity and oxidative stress, HTK patients seemed to be protected against severe acidosis, excessive fatty acid oxidation, and inflammation during ischemia-reperfusion. Additional studies are needed to confirm these findings.

Pulmonary artery perfusion versus no perfusion during cardiopulmonary bypass for open heart surgery in adults

BACKGROUND

Available evidence has been inconclusive on whether pulmonary artery perfusion during cardiopulmonary bypass (CPB) is associated with decreased or increased mortality, pulmonary events, and serious adverse events (SAEs) after open heart surgery. To our knowledge, no previous systematic reviews have included meta-analyses of these interventions.

OBJECTIVES

To assess the benefits and harms of single-shot or continuous pulmonary artery perfusion with blood (oxygenated or deoxygenated) or a preservation solution compared with no perfusion during cardiopulmonary bypass (CPB) in terms of mortality, pulmonary events, serious adverse events (SAEs), and increased inflammatory markers for adult surgical patients.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Science Citation Index Expanded, and advanced Google for relevant studies. We handsearched retrieved study reports and scanned citations of included studies and relevant reviews to ensure that no relevant trials were missed. We searched for ongoing trials and unpublished trials in the World Health Organization International Clinical Trials Registry Platform (ICTRP) and at clinicaltrials.gov (4 July 2017). We contacted medicinal firms producing preservation solutions to retrieve additional studies conducted to examine relevant interventions.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared pulmonary artery perfusion versus no perfusion during CPB in adult patients (≧ 18 years).

DATA COLLECTION AND ANALYSIS

Two independent review authors extracted data, conducted fixed-effect and random-effects meta-analyses, and calculated risk ratios (RRs) or odds ratios (ORs) for dichotomous outcomes. For continuous data, we have presented mean differences (MDs) and 95% confidence intervals (CIs) as estimates of the intervention effect. To minimize the risk of systematic error, we assessed risk of bias of included trials. To reduce the risk of random errors caused by sparse data and repetitive updating of cumulative meta-analyses, we applied Trial Sequential Analyses (TSAs). We used GRADE principles to assess the quality of evidence.

MAIN RESULTS

We included in this review four RCTs (210 participants) reporting relevant outcomes. Investigators randomly assigned participants to pulmonary artery perfusion with blood versus no perfusion during CPB. Only one trial included the pulmonary artery perfusion intervention with a preservation solution; therefore we did not perform meta-analysis. Likewise, only one trial reported patient-specific data for the outcome "pulmonary events"; therefore we have provided no results from meta-analysis. Instead, review authors added two explorative secondary outcomes for this version of the review: the ratio of partial pressure of oxygen in arterial blood (PaO₂) to fraction of inspired oxygen (FiO₂); and intubation time. Last, review authors found no comparable data for the secondary outcome inflammatory markers.The effect of pulmonary artery perfusion on all-cause mortality was uncertain (Peto OR 1.78, 95% CI 0.43 to 7.40; TSA adjusted CI 0.01 to 493; 4 studies, 210 participants; GRADE: very low quality). Sensitivity analysis of one trial with overall low risk of bias (except for blinding of personnel during the surgical procedure) yielded no evidence of a difference for mortality (Peto OR 1.65, 95% CI 0.27 to 10.15; 1 study, 60 participants). The TSA calculated required information size was not reached and the futility boundaries did not cross; thus this analysis cannot refute a 100% increase in mortality.The effect of pulmonary artery perfusion with blood on SAEs was likewise uncertain (RR 1.12, 95% CI 0.66 to 1.89; 3 studies, 180 participants; GRADE: very low quality). Data show an association between pulmonary artery perfusion with blood during CPB and a higher postoperative PaO₂/FiO₂ ratio (MD 27.80, 95% CI 5.67 to 49.93; 3 studies, 119 participants; TSA adjusted CI 5.67 to 49.93; GRADE: very low quality), although TSA could not confirm or refute a 10% increase in the PaO₂/FiO₂ ratio, as the required information size was not reached.

AUTHORS' CONCLUSIONS

The effects of pulmonary artery perfusion with blood during cardiopulmonary bypass (CPB) are uncertain owing to the small numbers of participants included in meta-analyses. Risks of death and serious adverse events may be higher with pulmonary artery perfusion with blood during CPB, and robust evidence for any beneficial effects is lacking. Future randomized controlled trials (RCTs) should provide long-term follow-up and patient stratification by preoperative lung function and other documented risk factors for mortality. One study that is awaiting classification (epub abstract with preliminary results) may change the results of this review when full study details have been published.

Pulmonary artery perfusion versus no pulmonary perfusion during cardiopulmonary bypass in patients with COPD: a randomised clinical trial

Introduction

Absence of pulmonary perfusion during cardiopulmonary bypass (CPB) may be associated with reduced postoperative oxygenation. Effects of active pulmonary artery perfusion were explored in patients with chronic obstructive pulmonary disease (COPD) undergoing cardiac surgery.

Methods

90 patients were randomised to receive pulmonary artery perfusion during CPB with either oxygenated blood (n=30) or histidine-tryptophan-ketoglutarate (HTK) solution (n=29) compared with no pulmonary perfusion (n=31). The coprimary outcomes were the inverse oxygenation index compared at 21 hours after starting CPB and longitudinally in a mixed-effects model (MEM). Secondary outcomes were tracheal intubation time, serious adverse events, mortality, days alive outside the intensive care unit (ICU) and outside the hospital.

Results

21 hours after starting CPB patients receiving pulmonary artery perfusion with normothermic oxygenated blood had a higher oxygenation index compared with no pulmonary perfusion (mean difference (MD) 0.94; 95% CI 0.05 to 1.83; p=0.04). The blood group had also a higher oxygenation index both longitudinally (MEM, p=0.009) and at 21 hours (MD 0.99; CI 0.29 to 1.69; p=0.007) compared with the HTK group. The latest result corresponds to a difference in the arterial partial pressure of oxygen of 23 mm Hg with a median fraction of inspired oxygen of 0.32. Yet the blood or HTK groups did not demonstrate a longitudinally higher oxygenation index compared with no pulmonary perfusion (MEM, p=0.57 and 0.17). Similarly, at 21 hours there was no difference in the oxygenation index between the HTK group and those no pulmonary perfusion (MD 0.06; 95% CI −0.73 to 0.86; p=0.87). There were no statistical significant differences between the groups for the secondary outcomes.

Discussion

Pulmonary artery perfusion with normothermic oxygenated blood during cardiopulmonary bypass appears to improve postoperative oxygenation in patients with COPD undergoing cardiac surgery. Pulmonary artery perfusion with hypothermic HTK solution does not seem to improve postoperative oxygenation.

Trial registration number

NCT01614951; Pre-results.

Effective pulmonary artery perfusion mode during cardiopulmonary bypass

AIM

Reducing lung injury during cardiopulmonary bypass (CPB) is important for patients' recovery. The present study was designed to research convenient and effective pulmonary artery perfusion mode during CPB in an animal model.

METHODS

Twelve healthy mongrel dogs were randomly divided into 2 groups: a control group and a perfusion group designed to simulate clinical CPB-induced lung injury. During CPB, pulmonary artery perfusion with modified low-potassium dextran (LPD) solution was performed immediately after the initiation of ischemia and before reperfusion for 3 to 4 minutes each time, with pressure maintained at 15 to 20 mmHg; animals in the control group were not perfused. After pulmonary reperfusion, the changes in pulmonary function and tissue biochemical data were determined.

RESULTS

Compared with the control group, lung compliance, oxygenation, and vascular resistance after reperfusion were significantly improved in the perfusion group. The malonaldehyde concentration, neutrophil sequestration ratio, and tissue water content also decreased significantly in the perfusion group.

CONCLUSION

The pulmonary artery perfusion mode used in this experiment could relieve CPB-induced lung injury effectively. Improving cellular tolerance to hypoxia and decreasing inflammatory reaction may be the important mechanisms. Moreover, this mode is convenient and does not interfere with the intended operations, which is promising for clinical use.

Ischaemic post-conditioning protects lung from ischaemia-reperfusion injury by up-regulation of haeme oxygenase-1

OBJECTIVE

The emergence of ischaemic post-conditioning (IPO) provides a potential method for experimentally and clinically attenuating various types of organ injuries. There has been little work, however, examining its effects in the setting of lung ischaemia reperfusion (IR). The stress protein, haeme oxygenase-1 (HO-1), has been found to exert a potent, protective role in a variety of lung injury models. In this study, we hypothesised that the induction of HO-1 by IPO plays a protective role against the deleterious effects of IR in the lung.

METHODS

Anaesthetised and mechanically ventilated adult Sprague-Dawley rats were randomly assigned to one of the following groups (n=8 each): the sham-operated control group, the IR group (40 min of left-lung ischaemia and 105 min of reperfusion), the IPO group (three successive cycles of 30-s reperfusion per 30-s occlusion before restoring full perfusion) and the ZnPPIX+IPO group (ZnPPIX, an inhibitor of HO-1, was injected intra-peritoneally at 20 mg kg(-1) 24h prior to the experiment and the rest of the procedures were similar to that of the IPO group). Lung injury was assessed by arterial blood gas analysis, wet-to-dry lung weight ratio and tissue histological changes. The extent of lipid peroxidation was determined by measuring plasma levels of malondialdehyde (MDA) production. Expression of HO-1 was determined by immunohistochemistry.

RESULTS

Lung IR resulted in a significant reduction of PaO(2) (data in IR, P<0.05 vs. data in sham) and increase of lung wet-to-dry weight ratio, accompanied with increased MDA production and severe lung pathological morphological changes as well as a compensatory increase in HO-1 protein expression, as compared with sham (All P<0.05). IPO markedly attenuated all the above pathological changes seen in the IR group and further increased HO-1 expression. Treatment with ZnPPIX abolished all the protective effects of post-conditioning.

CONCLUSION

It may be concluded that IPO protects IR-induced lung injury via induction of HO-1.

Pulmonary perfusion with L-arginine ameliorates post-cardiopulmonary bypass lung injury in a rabbit model

BACKGROUND

Post-cardiopulmonary bypass (CPB) lung injury is the combination of whole body inflammatory response and local ischemia-reperfusion (IR) injury. We investigated the benefit of pulmonary perfusion with L-arginine in protection against post-CPB lung injury.

METHODS

New Zealand white rabbits (n = 50, weight, 2.5-2.8 kg) were divided into five groups (n = 10 each): sham (sham sternotomy), CPB (CPB without pulmonary perfusion), perfusion (CPB with pulmonary perfusion), L-arginine (CPB with perfusion + L-arginine), and L-NAME (CPB with perfusion + L-NAME). The duration of CPB was 60 min followed by 2 h of reperfusion. Pulmonary perfusion was performed every 20 min through the pulmonary artery during CPB. Checking parameters included: (1) pulmonary vascular resistance, (2) pulmonary artery endothelium relaxation (organ chamber study), and (3) IR marker (myeloperoxidase) and inflammatory markers (TNF-α, IL-B, NF-κB).

RESULTS

CPB induced pulmonary artery endothelium dysfunction manifested by increased pulmonary vascular resistance and impaired pulmonary artery relaxation. Pulmonary perfusion could significantly reverse the phenomenon (P < 0.01) while provision of NO precursor-L-arginine with pulmonary perfusion together further possessed significant relaxation ability for pulmonary arterial endothelium compared with perfusion alone (P < 0.05). Accordingly, lung parenchyma myeloperoxidase activity and inflammatory cytokine level were also markedly increased after CPB (P < 0.05). Pulmonary perfusion could partially decrease the response, whereas additional L-arginine further attenuated inflammatory cytokine release (P < 0.05).

CONCLUSIONS

Pulmonary perfusion during CPB partially ameliorates CPB-induced lung injury. Pulmonary perfusion with L-arginine could further attenuate lung injury by restoring endothelial function and decreasing inflammatory response.

A novel and stable "two-hit" acute lung injury model induced by oleic acid in piglets

Background

Children are susceptible to pulmonary injury, and acute lung injury (ALI) often results in a high mortality and financial cost in pediatric patients. Evidence has showed that oleic acid (OA) plays an important role in ALI. Therefore, it has special significance to study ALI in pediatric patients by using OA-induced animal models. Unfortunately, the animal model hs a high mortality due to hemodynamic instability. The aim of this study was to establish a novel hemodynamically stable OA-induced ALI model in piglets with two hits.

Methods

18 Chinese mini-piglets were randomized into three groups: group C (received saline-ethanol solution), group T (received OA-ethanol solution in routine administration manner) and group H (received OA-ethanol solution in two-hit manner). Hemodynamic and pulmonary function data were measured. Histopathological assessments were performed.

Results

Two piglets in group T died of radical decline of systemic blood pressure. Group T showed more drastic hemodynamic changes than group H especially during the period of 5 to 30 minutes after OA administration. Both Group T and group H all produced severe lung injury, while group C had no significant pathologic changes. OA-induced hypotension might be caused by pulmonary hypertension rather than comprised left ventricular function.

Conclusion

OA leads to severe pulmonary hypertension which results in hemodynamic fluctuation in OA-induced ALI model. It is the first report on hemodynamic stable ALI animal model in piglets using two-hit method. The two-hit ALI animal model fulfils the ALI criteria and has the following characteristics: hemodynamic stability, stable damage to gas exchange and comparability with pediatric patients in body weight and corresponding age. The two-hit ALI animal model can be used to study the basic mechanism and the therapeutic strategies for pediatric ALI.

Continuous pulmonary infusion of L-arginine during deep hypothermia and circulatory arrest improves pulmonary surfactant integrity in piglets

BACKGROUND

The integrity of pulmonary surfactant (PS) is impaired during deep hypothermia and circulatory arrest (DHCA), a preferred bypass strategy for infants undergoing complex cardiac operations, due mainly to bypass-induced systemic inflammation. The requirement of L-arginine, a precursor of nitric oxide, is elevated during acute pulmonary inflammation. We hypothesized that continuous intrapulmonary supplementation of L-arginine during DHCA can maintain the integrity of PS metabolism and thus protect the pulmonary function.

METHODS

Sixteen piglets underwent 90-minute circulatory arrest at 18 degrees C before rewarming. During circulatory arrest, antegrade infusion of Ringer's lactate solution alone (n = 8) or containing L-arginine (1 mg/kg/min, n = 8) was initiated into the pulmonary circulation. Disaturated phosphatidylcholine, total phospholipids, and total proteins from tracheal aspirates were measured serially until the experiment ended (4 hours after rewarming). Various variables of pulmonary function were also monitored.

RESULTS

L-arginine led to less decrement of disaturated phosphatidylcholine/total phospholipids and disaturated phosphatidylcholine/total proteins after DHCA. At 4 hours after rewarming, L-arginine had significantly mitigated the deterioration of pulmonary static compliance (3.6 +/- 0.5 vs 3.3 +/- 0.3 mL/cm H2O) and partial pressure of arterial oxygen/fraction of inspired oxygen (330 +/- 48 vs 296 +/- 32 mm Hg). Pulmonary retention of water (6.2 +/- 1.0 vs 5.5 +/- 1.2) was significantly reduced. The L-arginine-treated group showed an increase in NO metabolites (NO2-/NO3-) from the pulmonary circulation, the extent of which is correlated to PS content.

CONCLUSIONS

Continuous L-arginine supplementation during DHCA attenuated PS depletion and, therefore, ameliorated postoperative pulmonary dysfunction.

Lung perfusion with clarithromycin ameliorates lung function after cardiopulmonary bypass

BACKGROUND

Macrolides antibiotics may affect neutrophil functions that correlate with the inflammation induced by cardiopulmonary bypass. Our study observed the protective effect of clarithromycin on inflammatory lung injury after cardiopulmonary bypass.

METHODS

Twelve adult sheep were randomly divided into two groups. After cardiopulmonary bypass was established, the lung was perfused through the pulmonary artery with either dextran solution (30 mL/kg) in the control group (n = 6) or dextran solution added to clarithromycin (10 mg/kg) in the experimental group (n = 6). Bypass was withdrawn after 90 minutes. Pulmonary function was determined and inflammatory factors were analyzed. Apoptotic neutrophils in the lung were assayed and lung biopsies were also performed.

RESULTS

Pulmonary vascular resistance (102.2 +/- 14.0 dyne.s.cm(-5)) was lower in the experimental group compared with the control group (202.6 +/- 47.3 dyne.s.cm(-5), p < 0.01) whereas the oxygen index was higher in the experimental group (p < 0.05). Plasma myeloperoxidase in the experimental group (0.015 +/- 0.006 U/L) was lower than that in the control group (0.029 +/- 0.007 U/L, p < 0.01). Plasma interlukin-8 (0.18 +/- 0.04 ug/L) and tumor necrosis factor (1.00 +/- 0.13 ug/L) in the experimental group were lower than in the control group (0.39 +/- 0.09 ug/L, 1.55 +/- 0.35 ug/L, p < 0.01). Histologic analyses showed intra-alveolar hemorrhage and neutrophil accumulation in the control group, whereas there were no significant changes in the experimental group. The apoptosis rate of accumulated neutrophils was significantly lower in the control group (p < 0.01).

CONCLUSIONS

Lung perfusion with hypothermic protective solution containing clarithromycin distinctly inhibits inflammatory responses caused by cardiopulmonary bypass and ameliorates lung function.