Pulmonary perfusion with oxygenated blood or custodiol HTK solution during cardiac surgery for postoperative pulmonary function in COPD patients: a trial protocol for the randomized, clinical, parallel group, assessor and data analyst blinded Pulmonary Protection Trial

BACKGROUND: Five to thirty percent of patients undergoing cardiac surgery present with chronic obstructive pulmonary disease (COPD) and have a 2- to 10-fold higher 30-day mortality risk. Cardiopulmonary bypass (CPB) creates a whole body systemic inflammatory response syndrome (SIRS) that could impair pulmonary function. Impaired pulmonary function can, however, be attenuated by pulmonary perfusion with oxygenated blood or custodiol HTK (histidine-tryptophan-ketoglutarate) solution. METHODS/DESIGN: The Pulmonary Protection Trial (PP-Trial) randomizes 90 patients undergoing CPB-dependent cardiac surgery to evaluate whether pulmonary perfusion with oxygenated blood or custodiol HTK solution reduces postoperative pulmonary dysfunction in COPD patients. Further, we aim for a non-randomized evaluation of postoperative pulmonary function after transcatheter aortic-valve implantation (TAVI). The primary outcome measure is the oxygenation index measured from anesthesia induction to the end of surgery and until 24 hours after anesthesia induction for a total of six evaluations. DISCUSSION: Patients with COPD may be impaired by hypoxemia and SIRS. Thus, prolonged recovery and even postoperative complications and death may be reflected by the degree of hypoxemia and SIRS. The limited sample size does not aim for confirmatory conclusions on mortality, cardiovascular complications or risk of pneumonia and sepsis, but the PP-Trial is considered an important feasibility trial paving the road for a multicenter confirmatory trial. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01614951

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

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 perfusion with oxygenated blood or custodiol HTK solution during cardiac surgery for postoperative pulmonary function in COPD patients: a trial protocol for the randomized, clinical, parallel group, assessor and data analyst blinded Pulmonary Protection Trial

Abstract Background Five to thirty percent of patients undergoing cardiac surgery present with chronic obstructive pulmonary disease (COPD) and have a 2- to 10-fold higher 30-day mortality risk. Cardiopulmonary bypass (CPB) creates a whole body systemic inflammatory response syndrome (SIRS) that could impair pulmonary function. Impaired pulmonary function can, however, be attenuated by pulmonary perfusion with oxygenated blood or custodiol HTK (histidine-tryptophan-ketoglutarate) solution. Methods/Design The Pulmonary Protection Trial (PP-Trial) randomizes 90 patients undergoing CPB-dependent cardiac surgery to evaluate whether pulmonary perfusion with oxygenated blood or custodiol HTK solution reduces postoperative pulmonary dysfunction in COPD patients. Further, we aim for a non-randomized evaluation of postoperative pulmonary function after transcatheter aortic-valve implantation (TAVI). The primary outcome measure is the oxygenation index measured from anesthesia induction to the end of surgery and until 24 hours after anesthesia induction for a total of six evaluations. Discussion Patients with COPD may be impaired by hypoxemia and SIRS. Thus, prolonged recovery and even postoperative complications and death may be reflected by the degree of hypoxemia and SIRS. The limited sample size does not aim for confirmatory conclusions on mortality, cardiovascular complications or risk of pneumonia and sepsis, but the PP-Trial is considered an important feasibility trial paving the road for a multicenter confirmatory trial. Trial registration ClinicalTrials.gov: NCT01614951.</p

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

Detailed statistical analysis plan for the pulmonary protection trial

BACKGROUND: Pulmonary dysfunction complicates cardiac surgery that includes cardiopulmonary bypass. The pulmonary protection trial evaluates effect of pulmonary perfusion on pulmonary function in patients suffering from chronic obstructive pulmonary disease. This paper presents the statistical plan for the main publication to avoid risk of outcome reporting bias, selective reporting, and data-driven results as an update to the published design and method for the trial. RESULTS: The pulmonary protection trial is a randomized, parallel group clinical trial that assesses the effect of pulmonary perfusion with oxygenated blood or Custodiol™ HTK (histidine-tryptophan-ketoglutarate) solution versus no pulmonary perfusion in 90 chronic obstructive pulmonary disease patients. Patients, the statistician, and the conclusion drawers are blinded to intervention allocation. The primary outcome is the oxygenation index from 10 to 15 minutes after the end of cardiopulmonary bypass until 24 hours thereafter. Secondary outcome measures are oral tracheal intubation time, days alive outside the intensive care unit, days alive outside the hospital, and 30- and 90-day mortality, and one or more of the following selected serious adverse events: pneumothorax or pleural effusion requiring drainage, major bleeding, reoperation, severe infection, cerebral event, hyperkaliemia, acute myocardial infarction, cardiac arrhythmia, renal replacement therapy, and readmission for a respiratory-related problem. CONCLUSIONS: The pulmonary protection trial investigates the effect of pulmonary perfusion during cardiopulmonary bypass in chronic obstructive pulmonary disease patients. A preserved oxygenation index following pulmonary perfusion may indicate an effect and inspire to a multicenter confirmatory trial to assess a more clinically relevant outcome. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01614951, registered on 6 June 2012 ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1745-6215-15-510) contains supplementary material, which is available to authorized users