Pulmonary reimplantation response in single-lung transplantation

Interobserver variability in the evaluation of primary graft dysfunction after lung transplantation: impact of radiological training and analysis of discordant cases

PURPOSE

Radiologic criteria for the diagnosis of primary graft dysfunction (PGD) after lung transplantation are nonspecific and can lead to misinterpretation. The primary aim of our study was to assess the interobserver agreement in the evaluation of chest X-rays (CXRs) for PGD diagnosis and to establish whether a specific training could have an impact on concordance rates. Secondary aim was to analyze causes of interobserver discordances.

MATERIAL AND METHODS

We retrospectively enrolled 164 patients who received bilateral lung transplantation at our institution, between February 2013 and December 2019. Three radiologists independently reviewed postoperative CXRs and classified them as suggestive or not for PGD. Two of the Raters performed a specific training before the beginning of the study. A senior thoracic radiologist subsequently analyzed all discordant cases among the Raters with the best agreement. Statistical analysis to calculate interobserver variability was percent agreement, Cohen's kappa and intraclass correlation coefficient.

RESULTS

A total of 473 CXRs were evaluated. A very high concordance among the two trained Raters, 1 and 2, was found (K = 0.90, ICC = 0.90), while a poorer agreement was found in the other two pairings (Raters 1 and 3: K = 0.34, ICC = 0.40; Raters 2 and 3: K = 0.35, ICC = 0.40). The main cause of disagreement (52.4% of discordant cases) between Raters 1 and 2 was the overestimation of peribronchial thickening in the absence of unequivocal bilateral lung opacities or the incorrect assessment of unilateral alterations.

CONCLUSION

To properly identify PGD, it is recommended for radiologists to receive an adequate specific training.

Primary Graft Dysfunction

Primary graft dysfunction (PGD) is a form of acute lung injury after transplantation characterized by hypoxemia and the development of alveolar infiltrates on chest radiograph that occurs within 72 hours of reperfusion. PGD is among the most common early complications following lung transplantation and significantly contributes to increased short-term morbidity and mortality. In addition, severe PGD has been associated with higher 90-day and 1-year mortality rates compared with absent or less severe PGD and is a significant risk factor for the subsequent development of chronic lung allograft dysfunction. The International Society for Heart and Lung Transplantation released updated consensus guidelines in 2017, defining grade 3 PGD, the most severe form, by the presence of alveolar infiltrates and a ratio of PaO₂:FiO₂ less than 200. Multiple donor-related, recipient-related, and perioperative risk factors for PGD have been identified, many of which are potentially modifiable. Consistently identified risk factors include donor tobacco and alcohol use; increased recipient body mass index; recipient history of pulmonary hypertension, sarcoidosis, or pulmonary fibrosis; single lung transplantation; and use of cardiopulmonary bypass, among others. Several cellular pathways have been implicated in the pathogenesis of PGD, thus presenting several possible therapeutic targets for preventing and treating PGD. Notably, use of ex vivo lung perfusion (EVLP) has become more widespread and offers a potential platform to safely investigate novel PGD treatments while expanding the lung donor pool. Even in the presence of significantly prolonged ischemic times, EVLP has not been associated with an increased risk for PGD.

Postoperative acute respiratory distress syndrome in patients with previous exposure to bleomycin

OBJECTIVE

To determine the incidence and risk factors for postoperative acute respiratory distress syndrome (ARDS) in a large cohort of bleomycin-exposed patients undergoing surgery with general endotracheal anesthesia.

PATIENTS AND METHODS

From a Mayo Clinic cancer registry, we identified patients who had received systemic bleomycin and then underwent a major surgical procedure that required more than 1 hour of general anesthesia from January 1, 2000, through August 30, 2012. Heart, lung, and liver transplantations were excluded. Postoperative ARDS (within 7 days after surgery) was defined according to the Berlin criteria.

RESULTS

We identified 316 patients who underwent 541 major surgical procedures. Only 7 patients met the criteria for postoperative ARDS; all were white men, and 6 were current or former smokers. On univariate analysis, we observed an increased risk of postoperative ARDS in patients who were current or former smokers. Furthermore, significantly greater crystalloid and colloid administration was found in patients with postoperative ARDS. We also observed a trend toward longer surgical duration and red blood cell transfusion in patients with postoperative ARDS, although this finding was not significant. Intraoperative fraction of inspired oxygen was not associated with postoperative ARDS. In bleomycin-exposed patients, the incidence of postoperative ARDS after major surgery with general anesthesia is approximately 1.3% (95% CI, 0.6%-2.6%). For first major procedures after bleomycin therapy, the incidence is 1.9% (95% CI, 0.9%-4.1%).

CONCLUSION

The risk of postoperative ARDS in patients exposed to systemic bleomycin appears to be lower than expected. Smoking status may be an important factor that modifies the risk of postoperative ARDS in these patients.

Prednisolone as preservation additive prevents from ischemia reperfusion injury in a rat model of orthotopic lung transplantation

The lung is, more than other solid organs, susceptible for ischemia reperfusion injury after orthotopic transplantation. Corticosteroids are known to potently suppress pro-inflammatory processes when given in the post-operative setting or during rejection episodes. Whereas their use has been approved for these clinical indications, there is no study investigating its potential as a preservation additive in preventing vascular damage already in the phase of ischemia. To investigate these effects we performed orthotopic lung transplantations (LTX) in the rat. Prednisolone was either added to the perfusion solution for lung preservation or omitted and rats were followed for 48 hours after LTX. Prednisolone preconditioning significantly increased survival and diminished reperfusion edema. Hypoxia induced vasoactive cytokines such as VEGF were reduced. Markers of leukocyte invasiveness like matrix metalloprotease (MMP)-2, or common pro-inflammatory molecules like the CXCR4 receptor or the chemokine (C-C motif) ligand (CCL)-2 were downregulated by prednisolone. Neutrophil recruitment to the grafts was only increased in Perfadex treated lungs. Together with this, prednisolone treated animals displayed significantly reduced lung protein levels of neutrophil chemoattractants like CINC-1, CINC-2α/β and LIX and upregulated tissue inhibitor of matrix metalloproteinase (TIMP)-1. Interestingly, lung macrophage invasion was increased in both, Perfadex and prednisolone treated grafts, as measured by MMP-12 or RM4. Markers of anti-inflammatory macrophage transdifferentiation like MRC-1, IL-13, IL-4 and CD163, significantly correlated with prednisolone treatment. These observations lead to the conclusion that prednisolone as an additive to the perfusion solution protects from hypoxia triggered danger signals already in the phase of ischemia and thus reduces graft edema in the phase of reperfusion. Additionally, prednisolone preconditioning might also lead to macrophage polarization as a beneficial long-term effect.

Acute lung injury and acute respiratory distress syndrome: experimental and clinical investigations

Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) can be associated with various disorders. Recent investigation has involved clinical studies in collaboration with clinical investigators and pathologists on the pathogenetic mechanisms of ALI or ARDS caused by various disorders. This literature review includes a brief historical retrospective of ALI/ARDS, the neurogenic pulmonary edema due to head injury, the long-term experimental studies and clinical investigations from our laboratory, the detrimental role of NO, the risk factors, and the possible pathogenetic mechanisms as well as therapeutic regimen for ALI/ARDS.

Acute respiratory distress syndrome and lung injury: Pathogenetic mechanism and therapeutic implication

To review possible mechanisms and therapeutics for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). ALI/ARDS causes high mortality. The risk factors include head injury, intracranial disorders, sepsis, infections and others. Investigations have indicated the detrimental role of nitric oxide (NO) through the inducible NO synthase (iNOS). The possible therapeutic regimen includes extracorporeal membrane oxygenation, prone position, fluid and hemodynamic management and permissive hypercapnic acidosis etc. Other pharmacological treatments are anti-inflammatory and/or antimicrobial agents, inhalation of NO, glucocorticoids, surfactant therapy and agents facilitating lung water resolution and ion transports. β-adrenergic agonists are able to accelerate lung fluid and ion removal and to stimulate surfactant secretion. In conscious rats, regular exercise training alleviates the endotoxin-induced ALI. Propofol and N-acetylcysteine exert protective effect on the ALI induced by endotoxin. Insulin possesses anti-inflammatory effect. Pentobarbital is capable of reducing the endotoxin-induced ALI. In addition, nicotinamide or niacinamide abrogates the ALI caused by ischemia/reperfusion or endotoxemia. This review includes historical retrospective of ALI/ARDS, the neurogenic pulmonary edema due to head injury, the detrimental role of NO, the risk factors, and the possible pathogenetic mechanisms as well as therapeutic regimen for ALI/ARDS.

Ischemia of the lung causes extensive long-term pulmonary injury: an experimental study

Background

Lung ischemia-reperfusion injury (LIRI) is suggested to be a major risk factor for development of primary acute graft failure (PAGF) following lung transplantation, although other factors have been found to interplay with LIRI. The question whether LIRI exclusively results in PAGF seems difficult to answer, which is partly due to the lack of a long-term experimental LIRI model, in which PAGF changes can be studied. In addition, the long-term effects of LIRI are unclear and a detailed description of the immunological changes over time after LIRI is missing. Therefore our purpose was to establish a long-term experimental model of LIRI, and to study the impact of LIRI on the development of PAGF, using a broad spectrum of LIRI parameters including leukocyte kinetics.

Methods

Male Sprague-Dawley rats (n = 135) were subjected to 120 minutes of left lung warm ischemia or were sham-operated. A third group served as healthy controls. Animals were sacrificed 1, 3, 7, 30 or 90 days after surgery. Blood gas values, lung compliance, surfactant conversion, capillary permeability, and the presence of MMP-2 and MMP-9 in broncho-alveolar-lavage fluid (BALf) were determined. Infiltration of granulocytes, macrophages and lymphocyte subsets (CD45RA⁺, CD5⁺CD4⁺, CD5⁺CD8⁺) was measured by flowcytometry in BALf, lung parenchyma, thoracic lymph nodes and spleen. Histological analysis was performed on HE sections.

Results

LIRI resulted in hypoxemia, impaired left lung compliance, increased capillary permeability, surfactant conversion, and an increase in MMP-2 and MMP-9. In the BALf, most granulocytes were found on day 1 and CD5⁺CD4⁺ and CD5⁺CD8⁺-cells were elevated on day 3. Increased numbers of macrophages were found on days 1, 3, 7 and 90. Histology on day 1 showed diffuse alveolar damage, resulting in fibroproliferative changes up to 90 days after LIRI.

Conclusion

The short-, and long-term changes after LIRI in this model are similar to the changes found in both PAGF and ARDS after clinical lung transplantation. LIRI seems an independent risk factor for the development of PAGF and resulted in progressive deterioration of lung function and architecture, leading to extensive immunopathological and functional abnormalities up to 3 months after reperfusion.

Cytokine Profile After Lung Transplantation: Correlation With Allograft Injury

BACKGROUND

Post-lung transplant reperfusion edema (PLTRE) and its more severe form, primary graft failure (PGF), occur in 10% to 60% of lung transplant recipients. We hypothesized that PLTRE and PGF would be associated with an elevated proinflammatory cascade and that the allograft would be the source of cytokine appearance in the circulation.

METHODS

Pulmonary arterial and systemic arterial samples were obtained at baseline and at 4, 8, and 24 hours after reperfusion. Post-lung transplant reperfusion-edema and PGF were defined as PaO2/FiO2 less than 300 with a mild or moderate infiltrate, or less than 200 with a severe infiltrate and ventilator dependence after 72 hours, respectively. Tumor necrosis factor alpha (TNFalpha), interleukin (IL)-6, IL-8, and IL-10 concentrations were determined by immunoassay.

RESULTS

Fifteen single and 6 bilateral lung recipients were studied. Six (29%) had PLTRE and 4 (19%) had PGF; these patients had an overall elevation in plasma IL-6, IL-8, and IL-10 concentrations (all p < 0.05). Subgroup analysis revealed a significantly greater elevation in IL-6, IL-8, and IL-10 levels in PGF patients (all p < 0.01) versus PLTRE. In the PGF group, TNFalpha and IL-10 concentrations were significantly greater in the systemic versus the pulmonary arterial samples (p < 0.05).

CONCLUSIONS

Patients with PLTRE and PGF exhibited graded increases in IL-6, IL-8, and IL-10 concentrations. The PGF patients had higher TNFalpha and IL-10 systemic arterial concentrations overall, consistent with the allograft being a source of this cytokine production.

High Donor Age, Low Donor Oxygenation, and High Recipient Inotrope Requirements Predict Early Graft Dysfunction in Lung Transplant Recipients

BACKGROUND

Early dysfunction in lung transplants is characterized by poor oxygenation, which may then lead to prolonged mechanical ventilation. This may be due to a combination of donor, recipient, and management factors. Our aim was to determine the incidence and severity of hypoxia and graft dysfunction and which factors were directly associated with poor oxygenation within the first 24 hours after lung transplantation.

METHODS

A retrospective study of all 128 lung transplants between 1999 and 2002 was undertaken. Multiple linear regression analysis was performed to determine which donor, recipient, operative, and intensive care unit (ICU) parameters were associated with the worst recorded arterial blood gas partial pressure of oxygen (PAO2)/fraction of inspired oxygen (FIO2) ratio in the initial 24 hours after operation.

RESULTS

Eighty-three percent of the patients (104 of 128) had a PAO2/FIO2 ratio below 300 within the first 24 hours post-transplantation, and 60% (77 of 128) had a PAO2/FIO2 ratio below 200. A high donor age (p = 0.004), low donor PAO2 (p = 0.007), and high post-operative inotrope requirements (p = 0.02) were correlated with a low PAO2/FIO2 ratio. Recipient diagnosis, ischemic time, use of cardiopulmonary bypass, fluid balance in the ICU, and cardiac index were not related. There was no difference in the long-term outcomes of patients with high or low PAO2/FIO2 ratios.

CONCLUSIONS

A low PAO2/FIO2 ratio is a common finding in the first 24 hours after lung transplantation. Donor factors such as age and PAO2, and the need for increasing inotrope requirements in ICU predict early graft dysfunction and hypoxia.

Influence of Donor Characteristics on Outcome After Lung Transplantation: A Multicenter Study

BACKGROUND

The liberalization of lung-donor criteria and the use of marginal donors have been advocated to face the current shortage of donors in lung transplantation. However, the impact of donor characteristics on the outcome of lung transplantation is still largely unknown. We aimed to determine, on a large cohort of patients, the effect of donors characteristics on short- and long-term outcome of lung transplantation

METHODS

Between 1988 and 1998, a total of 785 adult patients underwent single-lung transplantation (n = 270), bilateral-lung transplantation (n = 251), and heart-lung transplantation (n = 264) in 7 centers in France. We constructed several multivariate models to assess the relationship between donor characteristics and early gas exchange, duration of mechanical ventilation, and long-term survival after lung transplantation.

RESULTS

Among donor characteristics, donor gas exchange before harvest was found to be significantly associated with recipient early gas exchange, duration of mechanical ventilation, and long-term survival after adjustment for potential confounding variables. Moreover, nonlinear modeling showed a steep increase in the relative risk of death when donor PaO2/FiO2 before harvest was below 350 (hazard ratio 1.43; 95% confidence interval 1.10-1.85; p = 0.01). Donor and recipient sex mismatch were also found to be significantly associated with long-term survival.

CONCLUSIONS

Although liberalization of lung-donor criteria may be considered to overcome the shortage of lung donors, our data suggest that the violation of the gas-exchange criterion should be avoided.

High central venous pressure is associated with prolonged mechanical ventilation and increased mortality after lung transplantation

BACKGROUND

Poor oxygenation might occur in transplanted lungs as a result of reperfusion injury and lack of lymphatic drainage. Low central venous and pulmonary capillary wedge pressures are advocated to reduce pulmonary edema and maximize oxygenation but might adversely affect cardiac index, circulation, and renal function.

METHODS

Histories, intensive care unit charts, and donor data on 118 lung transplantations performed between 1999 and 2002 were retrospectively assessed. Multiple logistic regression analysis was performed on donor, recipient, operative, and intensive care unit parameters to determine the relationship of filling pressure (central venous and pulmonary capillary wedge pressures) to prolonged mechanical ventilation and outcome. The mean central venous pressure was used to divide patients into high and low central venous pressure groups, which were then compared to determine differences in outcome and complication rates.

RESULTS

A high central venous pressure was found to be associated with prolonged mechanical ventilation (odds ratio, 1.57; 95% confidence interval, 1.13-2.20; P = .008). After removing the effect of poor myocardial function by excluding patients with low cardiac index (< 2.2 L x min -1 x m(-2) ) and high inotrope requirement (> 10 microg/min), central venous pressure remained associated with prolonged mechanical ventilation (odds ratio, 2.31; 95% confidence interval, 1.31-4.07; P = .004). Duration of ventilation (P < .001), intensive care unit mortality (P = .02), hospital mortality (P = .09), and 2-month mortality (P = .02) were higher in patients with central venous pressures of greater than 7 mm Hg. There was no evidence of complications caused by hypovolemia in the low (< or = 7 mm Hg) central venous pressure group, who had lower inotrope requirements (P = .02) and lower creatinine levels (P = .013). Conclusions A high central venous pressure was associated with adverse outcomes after lung transplantation.

Graft ischemic time and outcome of lung transplantation: a multicenter analysis

RATIONALE

The effect of graft ischemic time on early graft function and long-term survival of patients who underwent lung transplantation remains controversial. Consequently, graft ischemic time has not been incorporated in the decision-making process at the time of graft acceptance.

OBJECTIVES

To investigate the relationship between graft ischemic time and (1) early graft function and (2) long-term survival after lung transplantation.

MEASUREMENTS AND MAIN RESULTS

The data from 752 patients who underwent single lung transplantation (n = 258), bilateral lung transplantation (n = 247), and heart-lung transplantation (n = 247) in seven French transplantation centers during a 12-year period were reviewed. Independent data quality control was done to ensure the quality of the collected variables. Mean graft ischemic time was 245.8 +/- 96.4 minutes (range 50-660). After adjustment on 11 potential confounders, graft ischemic time was associated with the recipient Pa(O2)/FI(O2) ratio recorded within the first 6 hours and with long-term survival in patients undergoing single or double lung transplantation but not in patients undergoing heart-lung transplantation. The relationship between graft ischemic time and survival appears to be of cubic form with a cutoff value of 330 minutes. These results were unaffected by the preservation fluid employed.

CONCLUSIONS

The results of this large cohort of patients suggest a close relationship between graft ischemic time and both early gas exchange and long-term survival after single and double lung transplantation. Such relationship was not found in patients undergoing heart-lung transplantation. The expected graft ischemic time should be incorporated in the decision-making process at the time of graft acceptance.

Static inflation attenuates ischemia/reperfusion injury in an isolated rat lung in situ

STUDY OBJECTIVES

Ischemia (I)/reperfusion (R) lung injury is an important clinical issue in lung transplantation. In the present study, we observed the effects of lung static inflation, different perfusates, and ventilatory gas with nitrogen or oxygen on the I/R-induced pulmonary damage.

DESIGN AND SETTING

A total of 96 male Sprague-Dawley rats were used. The lung was isolated in situ.

METHODS

In an isolated lung, the capillary filtration coefficient (Kfc), lung weight gain (LWG), lung weight (LW)/body weight (BW) ratio, and protein concentration in BAL fluid (PCBAL) were measured or calculated to evaluate the degree of lung injury. Histologic examinations with hematoxylin-eosin staining were performed.

RESULTS

I/R caused lung injury, as reflected by increases in Kfc, LWG, LW/BW, and PCBAL. The histopathologic picture revealed the presence of hyaline membrane formation and the infiltration of inflammatory cells. These values were significantly attenuated by static lung inflation. The I/R lung damage appeared to be less in the lung perfused with whole blood than in the lung perfused with an isotonic solution. Therapy with ventilatory air (ie, nitrogen or oxygen) did not alter the I/R lung damage.

CONCLUSIONS

The data suggest that lung inflation is protective to I/R injury, irrespective of the type of ventilatory air used for treatment. The preservation of the lung for transplantation is better kept at a static inflation state and perfused with whole blood instead of an isotonic physiologic solution.

Clinical risk factors for primary graft failure following lung transplantation

STUDY OBJECTIVE

s: Primary graft failure (PGF) is a devastating acute lung injury syndrome following lung transplantation. We sought to identify donor, recipient, and operative risk factors for its development.

DESIGN

We conducted a cohort study of 255 consecutive lung transplant procedures performed between October 1991 and July 2000. We defined PGF as follows: (1) diffuse alveolar opacities exclusively involving allograft(s) and developing within 72 h of transplant, (2) a ratio of PaO(2) to fraction of inspired oxygen < 200 beyond 48 h postoperatively, and (3) no other secondary cause of graft dysfunction identified. Risk factors were assessed individually and adjusted for confounding using multivariable logistic regression models.

SETTING

Tertiary-care academic medical center.

RESULTS

The overall incidence was 11.8% (95% confidence interval [CI], 7.9 to 15.9). Following multivariable analysis, the risk factors independently associated with development of PGF were as follows: a recipient diagnosis of primary pulmonary hypertension (PPH; adjusted odds ratio [OR], 4.52; 95% CI, 1.29 to 15.9; p = 0.018), donor female gender (adjusted OR, 4.11; 95% CI, 1.17 to 14.4; p = 0.027), donor African-American race (adjusted OR, 5.56; 95% CI, 1.57 to 19.8; p = 0.008), and donor age < 21 years (adjusted OR, 4.06; 95% CI, 1.34 to 12.3; p = 0.013) and > 45 years (adjusted OR, 6.79; 95% CI, 1.61 to 28.5; p = 0.009).

CONCLUSIONS

Recipient diagnosis of PPH, donor African-American race, donor female gender, and donor age are independently and strongly associated with development of PGF.

Nitric oxide mediates lung injury induced by ischemia-reperfusion in rats

Nitric oxide (NO) has been reported to play a role in lung injury (LI) induced by ischemia-reperfusion (I/R). However, controversy exists as to the potential beneficial or detrimental effect of NO. In the present study, an in situ, perfused rat lung model was used to study the possible role of NO in the LI induced by I/R. The filtration coefficient (Kfc), lung weight gain (LWG), protein concentration in the bronchoalveolar lavage (PCBAL), and pulmonary arterial pressure (PAP) were measured to evaluate the degree of pulmonary hypertension and LI. I/R resulted in increased Kfc, LWG, and PCBAL. These changes were exacerbated by inhalation of NO (20-30 ppm) or 4 mM L-arginine, an NO precursor. The permeability increase and LI caused by I/R could be blocked by exposure to 5 mM N omega-nitro-L-arginine methyl ester (L-NAME; a nonspecific NO synthase inhibitor), and this protective effect of L-NAME was reversed with NO inhalation. Inhaled NO prevented the increase in PAP caused by I/R, while L-arginine had no such effect. L-NAME tended to diminish the I/R-induced elevation in PAP, but the suppression was not statistically significant when compared to the values in the I/R group. These results indicate that I/R increases Kfc and promotes alveolar edema by stimulating endogenous NO synthesis. Exogenous NO, either generated from L-arginine or delivered into the airway, is apparently also injurious to the lung following I/R.

Respiratory failure after lung transplantation

STUDY OBJECTIVES

To characterize patients who acquired postoperative respiratory failure after lung transplantation (LT), and to identify risks associated with postoperative respiratory failure and poor surgical outcome.

STUDY DESIGN

Retrospective clinical analysis in a tertiary care transplantation center.

METHODS

We reviewed the records of 80 consecutive patients who underwent LT from April 1994 to May 1999, analyzing their records for a number of preoperative and perioperative variables and complications.

RESULTS

Forty-four patients (55%) acquired postoperative respiratory failure and had a mortality rate of 45%. No difference was noted between patients with respiratory failure and those without in terms of age (mean +/- SD, 56 +/- 9 years vs 53 +/- 11 years), gender, baseline pretransplant arterial blood gas analysis (PaCO(2), 46 +/- 9 mm Hg vs 44 +/- 10 mm Hg), and cardiopulmonary exercise testing (maximum oxygen uptake, 0.76 +/- 0.44 L/min/m(2) vs 0.82 +/- 0.20 L/min/m(2)). Ischemic reperfusion lung injury (IRLI) [55%] and perioperative cardiovascular/hemorrhagic events (36%) were the major contributors to the development of respiratory failure. Preoperative pulmonary hypertension, right ventricular (RV) dysfunction, ischemic times, and need for bilateral LT and cardiopulmonary bypass (CPB) were higher in patients with respiratory failure (p < 0.05) compared to recipients without respiratory failure. However, the presence of preoperative moderate-to-severe RV dysfunction was the only independent factor (odds ratio, 21.9; 95% confidence interval, 1.6 to 309.0).

CONCLUSION

Respiratory failure after LT is common and is associated with high morbidity and mortality. Respiratory failure often occurred in patients with operative technical complications, cardiovascular events, and postoperative IRLI, which were observed most in patients requiring CPB because of RV dysfunction.

Non-immune acute graft injury after lung transplantation and the risk of subsequent bronchiolitis obliterans syndrome (BOS)

BACKGROUND

Primary graft dysfunction remains a major cause of early morbidity and mortality after lung transplantation. Evidence from animal models shows acute non-immune lung injury increases organ immunogenicity by enhancing MHC Class II expression. We hypothesized that acute non-immune injury in the lung allograft may impact, not only on early survival, but also on longer term survival by increasing the incidence of bronchiolitis obliterans syndrome (BOS).

METHODS

A single-center, retrospective, observational study in a population of over 320 lung transplant recipients was undertaken. The histologic diagnosis of diffuse alveolar damage (DAD) in an early graft biopsy was used to define those recipients at risk. Serial measurements of forced expiratory volume in 1 second (FEV(1)) in long-term follow-up defined the incidence of BOS.

RESULTS

Early graft biopsy was available in 291 of the recipients following transplantation. DAD was confirmed in 55 (19%); their 30-day survival (62.5%) was significantly worse than in recipients without DAD (87.5%; p < 0.0001, chi-square test). When 30-day deaths were excluded, however, there was no difference in survival between recipients with and without DAD (hazards ratio 0.69 [0.37 to 1.3]; p = 0.25, Wilcoxon's survival analysis). The incidence of subsequent BOS over the follow-up period was not significantly different in those with and without DAD on early biopsy at 46% and 59%, respectively (hazards ratio 0.88 [0.48 to 1.62]; p = 0.22, chi-square test). BOS did not occur any earlier in the DAD group (median 953 days, range 152 to 1,393) days compared with the non-DAD group (median 665 days, range 52 to 4,299) (p = 0.48, Fisher's exact test).

CONCLUSIONS

The development of severe non-immune acute graft injury after lung transplantation has a poor early prognosis. However, recipients with non-immune acute graft injury who survive >30 days show no significant difference in long-term survival or BOS-free time compared with recipients without early injury.

Primary graft failure following lung transplantation: predictive factors of mortality

STUDY OBJECTIVES

To assess incidence, outcome, and early predictors of mortality for patients with primary graft failure (PGF) following lung transplantation (LTx), and to develop an injury severity score able to accurately predict ICU mortality for these patients.

DESIGN

Retrospective cohort analysis.

SETTING

Two LTx centers in Paris.

PATIENTS

Two hundred fifty-nine patients who underwent LTx over a 12-year period.

MEASUREMENTS AND RESULTS

One hundred thirty-one patients (50.6%) met PGF criteria: radiographic graft infiltrate within the first 3 days following LTx associated with gas exchange impairment (PaO(2)/fraction of inspired oxygen ratio < 300 mm Hg). This syndrome was associated with an increased duration of mechanical ventilation (9.1 +/- 1 days vs 3.1 +/- 0.6 days, mean +/- SD; p < 0.001) and ICU mortality (29% vs 10.9%; p < 0.01). The patients with PGF were randomly assigned to developmental (n = 85) and validation (n = 46) samples. Using logistic regression analysis, four variables were found associated with ICU mortality in these patients: age, degree of gas exchange impairment, graft ischemic time, and severe early hemodynamic failure. An ischemia/reperfusion injury severity score was derived using these four variables. Model calibration was good in the developmental and validation samples, as was model discrimination (area under receiver operating characteristic curves, 0.93 and 0.85, respectively).

CONCLUSION

PGF following LTx is a frequent event, with significant ICU morbidity and mortality. We demonstrate that four simple factors allow prediction of ICU mortality with good accuracy.

Perioperative care of the lung transplant patient

Improvements in the perioperative management of lung transplant recipients have produced a 90% survival in the first 30 days following surgery. Detailed attention to donor organ procurement and preservation of the allograft are important in ensuring an early successful outcome. Early antibacterial administration based on donor or pretransplant cultures and antiviral therapy in CMV-negative recipients assist in avoiding early infectious complications. Development of hypoxemia or hemodynamic instability in the perioperative period requires a rapid, systematic evaluation with attention to mechanical, immunologic, or infectious causes. Nonpulmonary complications are not infrequent in lung transplant recipients.

[Single-lung transplant and primary graft failure]

OBJECTIVE

To quantify primary graft failure (PGF) and its impact on perioperative and early mortality in single-lung transplant (SLT).

METHOD

We analyzed 35 SLT procedures performed using similar techniques. PGF was defined as a PaO2/FiO2 coefficient lower than 200 mmHg during the first 72 hours or ventilation assistance lasting longer than 5 days attributable to primary lung dysfunction. We defined perioperative mortality as occurring within 30 days of surgery and early mortality within 90 days.

RESULTS

Twenty-five men and 10 women received lungs, 22 for pulmonary fibrosis and 13 for emphysema; the mean age was 53.26 10.77 years. Twenty right SLTs were performed and 15 left SLTs. Twenty-nine donors were men and 6 were women, with a mean age of 29.31 12.33 years. Twenty-six died from cranial trauma, 8 from stroke and 1 from a brain tumor. The mean time of intubation was 1.69 1.35 days. The mean PaO2 was 470.71 70.82 mmHg. The mean time of ischemia was 201.77 62.64 minutes. Four patients (11.42%) developed PGF and 3 died during the perioperative period. Two additional patients died within the early postoperative period. Survival was 91.4% at one month and 85.5% at three months. The cause of donor death was the only variable that influenced the development of PGF.

CONCLUSION

We observed a low incidence of PGF and of perioperative and early mortality, with one and three month survival rates similar to those reported internationally.

Reperfusion edema after lung transplantation: effect of daclizumab

PURPOSE

To determine if daclizumab, an interleukin-2 antagonist, reduced the severity of reperfusion edema in lung transplant recipients.

MATERIALS AND METHODS

Eighty-five patients who were to undergo 86 consecutive lung transplants were included; 43 (50%) received daclizumab in addition to conventional immunosuppression. Patients were assigned to one of the following groups: control, right allograft; control, left allograft; daclizumab treated, right allograft; daclizumab treated, left allograft. Radiographs obtained in the first 5 postoperative days were evaluated for degree of edema. Mean daily edema scores and curves for control and daclizumab-treated groups were compared. Differences in survival at 1, 3, 6, and 12 months after transplantation, days of mechanical ventilation, and the ratio of arterial oxygenation to inspired oxygen level at 1, 3, and 5 days after transplantation were also compared.

RESULTS

Mean daily edema scores, edema curves, survival, days of mechanical ventilation, and ratio of arterial oxygenation to inspired oxygen level at 1 and 3 days after transplantation did not significantly differ between daclizumab-treated and control groups. A trend toward improved survival in the daclizumab-treated group was noted.

CONCLUSION

Daclizumab had no effect on the radiographic or immediate clinical manifestations of reperfusion edema in lung transplant recipients. Additional follow-up is needed to determine if daclizumab offers any long-term benefit in terms of reduced rejection rates or survival.

Short-term "preconditioning" with inhaled nitric oxide protects rabbit lungs against ischemia-reperfusion injury

BACKGROUND

Pulmonary edema, owing to an impairment of microvascular barrier function, is an important feature in lung ischemia/reperfusion (IR) injury. Inhalation of nitric oxide (NO) during the period of reperfusion has previously been shown to reduce this leakage response.

METHODS

We investigated the impact of short-term (30 min) low-dose (10 ppm) pre-ischemic NO inhalation on IR injury in buffer-perfused rabbit lungs, subsequently undergoing 210 min of warm, anoxic-ventilated ischemia.

RESULTS

Far-reaching suppression of the leakage response, reflected by manifold increased capillary filtration coefficients and edema formation, was noted in lungs with pre-ischemic NO administration, corresponding to the beneficial effect of NO inhalation during reperfusion. The effect of NO pre-exposure was not related to vasodilation, because microvascular pressures were unchanged, and was mimicked by pre-ischemic intravascular administration of sodium nitroprusside with subsequent washout of this agent. NO inhalation during reperfusion, but not pre-ischemic, short-term NO administration, provoked a manifold increase in the accumulation of guanosine 3',5'-cyclic monophosphate (cGMP) in the perfusate. The cGMP-analogue, 8-Br-cGMP, mimicked the anti-edematous effect of NO when present during reperfusion, but pre-ischemic, short-term administration of 8-Br-cGMP provided only limited protection. The guanylate cyclase-inhibitor, 1H-[1, 2, 4]-Oxadiazolo-[4,3-a]-quinoxalin-1-one (ODQ), largely antagonized the beneficial effects of NO inhalation during reperfusion but had only minor influence on the effect of NO pre-exposure.

CONCLUSIONS

"Preconditioning" of the lung vasculature with short-term NO administration maintains endothelial integrity in a subsequent ischemia/reperfusion maneuver, with nonvasodilatory and non-cGMP-related mechanisms suggested to be largely responsible. This finding may offer interesting perspectives for donor management in clinical lung transplantation.

Influence of preservation solution on early graft failure in clinical lung transplantation

The aim of this study was to assess the influence of preservation solution type and extra- or intracellular composition on the occurrence of early graft dysfunction after clinical lung transplantation. For 170 patients who underwent a single (n = 124) or bilateral (n = 46) lung transplantation in two centers in Paris between 1988 and 1999, the preservation technique applied to the donor lung was single-flush perfusion of the pulmonary artery with one of several solutions of intracellular (Euro-Collins, n = 61; University of Wisconsin, n = 24) or extracellular composition (Cambridge, n = 64; Celsior, n = 21). The early postoperative outcome of these patients was reviewed. Reimplantation edema occurred in 48% of all patients, and the overall 1-mo survival rate was 84%. No significant difference in the incidence of edema, duration of mechanical ventilation, and 1-mo survival rate was observed between the four groups or between intra- and extracellular groups. After adjustment for graft ischemic time by means of multivariate analysis, the use of extracellular preservation fluid was associated with a lower incidence of reimplantation edema without effect on 1-mo mortality. Graft ischemic time was associated with both edema occurrence and 1-mo survival rate (p = 0.02 and p = 0.01, respectively). We conclude that extracellular-type solutions are associated with better lung preservation than intracellular-type solutions in clinical transplantation.

Aerosolized PGE1, PGI2 and nitroprusside protect against vascular leakage in lung ischaemia-reperfusion

High permeability oedema is an important feature in lung injury secondary to ischaemia-reperfusion. This study investigated the influence of aerosolized prostaglandin E1 (PGE1), prostaglandin I2 (PCI2) and the nitric oxide (NO)-donor, sodium nitroprusside (SNP) on microvascular barrier function in pulmonary ischaemia-reperfusion. Buffer-perfused rabbit lungs were exposed to 180 or 210 min of warm ischaemia while maintaining anoxic ventilation and a positive intravascular pressure. Reperfusion provoked a transient, mostly precapillary elevation of vascular resistance, followed by a severe increase of the capillary filtration coefficient (Kfc) versus nonischaemic controls (3.17+/-0.34 versus 0.85+/-0.05 cm3 x s(-1) cmH2O(-1) x g(-1) x 10(-4) after 30 min of reperfusion), and progressive oedema formation. Short-term aerosolization of SNP, PGE1 or PGI2 at the beginning of ischaemia largely suppressed the Kfc increase (1.36+/-0.22, 1.32+/-0.23 and 1.32+/-0.22 cm3 x s(-1) x cmH2O(-1) x g(-1) x 10(-4), respectively) and oedema formation. In contrast, application prior to reperfusion was much less effective, with some reduction of Kfc increase by PGI2 and SNP and no effect of PGE, (1.79+/-0.31, 2.2+/-0.53 and 3.2+/-0.05 cm3 x s(-1) x cmH2O(-1) x g(-1) x 10(-4), respectively). Haemodynamics, including microvascular pressure, were only marginally affected by the chosen doses of aerosolized vasodilators. It is concluded that short-term aerosolization of prostaglandin E1, prostaglandin I2 and sodium nitroprusside at the onset of ischaemia is highly effective in maintaining endothelial barrier properties in pulmonary ischaemia-reperfusion. This effect is apparently attributable to nonvasodilatory mechanisms exerted by these agents. Alveolar deposition of prostaglandins and/or nitric oxide donors by the aerosol technique may offer pulmonary protection in ischaemia-reperfusion injury.

Preventive effect of inhaled nitric oxide and pentoxifylline on ischemia/reperfusion injury after lung transplantation

BACKGROUND

The preventive effect of inhaled nitric oxide (NO) and pentoxifylline (PTX) administered during reperfusion has been demonstrated on experimental models of lung ischemia/reperfusion (I/R) injury but this strategy is not validated in clinical lung transplantation. The aim of this study was to assess retrospectively the protective effect of inhaled NO and PTX after lung transplantation.

METHODS

Twenty-three consecutive patients who received inhaled NO (10 ppm) and PTX (NO-PTX group) at the time of reperfusion were compared retrospectively with (1) 23 consecutive patients transplanted just before the use of NO-PTX (control group 23); (2) 95 patients representing all the patients of the series who did not receive NO-PTX (control group 95), with respect to I/R injury related complications. In particular, the incidence of pulmonary reimplantation edema and early hemodynamic failure, the PaO2/FIO2 ratio as well as the duration of mechanical ventilation and the 2-month mortality rates were compared.

RESULTS

Reimplantation edema was observed in 6/23 patients (26%) in the NO-PTX group vs. 13/23 patients (56%) in the control group 23 (P=0.035) and 48/95 patients (50%) in the control group 95 (P=0.035). The worst PaO2/FIO2 ratio during the first three postoperative days was 240-102 mmHg in the NO-PTX group vs. 162+/-88 mmHg (P=0.01) and 176+/-107 mmHg (P=0.01) in the control group 23 and the control group 95, respectively. The duration of mechanical ventilation was 2.1+/-2.4 days in the NO-PTX group vs. 7+/-9 days in the control group 23 (P=0.02) and 6+/-7 days in the control group 95 (P=0.01). The 2-month mortality rate was 4.3% in the NO-PTX group vs. 26% (P=0.04) and 21% (P=0.07) in the control group 23 and the control group 95, respectively.

CONCLUSIONS

The marked decrease in the incidence of allograft dysfunction compared with two historical control groups suggests that PTX and inhaled NO given before and throughout reperfusion are protective against I/R injury in the setting of clinical transplantation.

Protection against gas exchange abnormalities by pre-aerosolized PGE1, iloprost and nitroprusside in lung ischemia-reperfusion

BACKGROUND

Development of severe gas exchange abnormalities and respiratory failure is a major threat in lung transplantation.

METHODS

We used a model of ischemia-reperfusion injury in buffer-perfused rabbit lungs, with gas exchange conditions being analyzed in detail by the multiple inert gas elimination technique. A total of 150 min of warm ischemia was performed, and anoxic ventilation and a positive intravascular pressure were maintained throughout the ischemic period.

RESULTS

Reperfusion provoked a transient, mostly precapillary pulmonary artery pressure elevation and progressive lung edema formation attributable to increased capillary permeability. Severe ventilation-perfusion mismatch with predominance of shunt flow became apparent within minutes after onset of reperfusion. 5 min-aerosolization maneuvers for alveolar deposition of prostaglandin E1, the long-acting prostacyclin analogue iloprost or the nitric oxide donor agent sodium nitroprusside were undertaken at the onset of ischemia. All preaerosolized vasodilator agents markedly reduced the pulmonary artery pressure elevation and the leakage response upon reperfusion. Most impressively, maintenance of physiological ventilation-perfusion matching was achieved by these maneuvers, and the development of shunt flow was largely suppressed.

CONCLUSIONS

Preischemic alveolar deposition of PGE1, iloprost, and sodium nitroprusside by aerosol technique is highly effective in conserving normal pulmonary hemodynamics, microvascular integrity, and physiological gas exchange conditions upon reperfusion. This approach may offer as new strategy for maintenace of pulmonary function in lung transplantation.

The PDE inhibitor zaprinast enhances NO-mediated protection against vascular leakage in reperfused lungs

Disruption of endothelial barrier properties with development of noncardiogenic pulmonary edema is a major threat in lung ischemia-reperfusion (I/R) injury that occurs under conditions of lung transplantation. Inhaled nitric oxide (NO) reduced vascular leakage in lung I/R models, but the efficacy of this agent may be limited. We coadministered NO and zaprinast, a cGMP-specific phosphodiesterase inhibitor, to further augment the NO-cGMP axis. Isolated, buffer-perfused rabbit lungs were exposed to 4.5 h of warm ischemia. Reperfusion provoked a transient elevation in pulmonary arterial pressure and a negligible rise in microvascular pressure followed by a massive increase in the capillary filtration coefficient and severe lung edema formation. Inhalation of 10 parts/million of NO or intravascular application of 100 microM zaprinast on reperfusion both reduced pressor response and moderately attenuated vascular leakage. Combined administration of both agents induced no additional vasodilation at constant microvascular pressures, but additively protected against capillary leakage paralleled by a severalfold increase in perfusate cGMP levels. In conclusion, combining low-dose NO inhalation and phosphodiesterase inhibition may be suitable for the maintenance of graft function in lung transplantation by amplifying the beneficial effect of the NO-cGMP axis and avoiding toxic effects of high NO doses.

Lung deflation impairs alveolar epithelial fluid transport in ischemic rabbit and rat lungs

BACKGROUND

Because the fluid transport capacity of the alveolar epithelium after lung ischemia with and without lung deflation has not been well studied, we carried out experimental studies to determine the effect of lung deflation on alveolar fluid clearance.

METHODS

After 1 or 2 hr of ischemia, we measured alveolar fluid clearance using 125I-albumin and Evans blue-labeled albumin concentrations in in vivo rabbit lungs in the presence of pulmonary blood flow and in ex vivo rat lungs in the absence of any pulmonary perfusion, respectively.

RESULTS

The principal results were: (1) lung deflation decreased alveolar fluid clearance while inflation of the lungs during ischemia preserved alveolar fluid clearance in both in vivo and ex vivo studies; (2) alveolar fluid clearance was normal in the rat lungs inflated with nitrogen (thus, alveolar gas composition did not affect alveolar fluid clearance); (3) amiloride-dependent alveolar fluid clearance was preserved when the lungs were inflated during ischemia; (4) terbutaline-simulated alveolar fluid clearance was preserved in the hypoxic rat lungs inflated with nitrogen; (5) lecithinized superoxide dismutase, a scavenger of superoxide anion, and N(omega)-nitro-L-arginine methyl ester, an inhibitor of nitric oxide, preserved normal alveolar fluid clearance in the deflated rat lungs.

CONCLUSION

Lung deflation decreases alveolar fluid clearance by superoxide anion- and nitric oxide-dependent mechanisms.

Ventilation-perfusion mismatch after lung ischemia-reperfusion. Protective effect of nitric oxide

Lung ischemia-reperfusion provokes pulmonary hypertension and increased microvascular permeability with subsequent edema formation and hypoxemia. We exposed buffer-perfused rabbit lungs to 120 and 180 min of warm ischemia. After reperfusion, gas exchange disturbances were analyzed by the multiple inert gas elimination technique (MIGET). Additionally, ischemic lungs were treated with different doses of inhaled nitric oxide (NO) throughout reperfusion. Reperfusion provoked a transient pulmonary artery pressure elevation, followed by progressive pulmonary edema formation. After 120 min of ischemia, severe ventilation-perfusion (V A/Q) mismatch developed within 15 min of reperfusion, with the appearance of low V A/Q areas and marked broadening of both perfusion and ventilation distribution in the midrange V A/Q regions. In parallel, shunt flow increased from less than 2% to approximately 17%. Inhalation of NO suppressed the pressor response, edema formation, as well as V A/Q mismatch and shunt flow. Concentrations of 10 and 50 ppm NO were equipotent, surpassing the efficacy of 1 or 250 ppm NO. Inhalation of NO, however, did not protect from the overwhelming gas exchange and fluid balance disturbances provoked by 180 min ischemia. In conclusion, severe abnormalities in gas exchange occurred rapidly upon reperfusion of ischemic lungs. Prophylactic NO inhalation may be considered for maintenance of gas exchange in settings of ischemia-reperfusion including lung transplantation.

Acute pulmonary edema after lung transplantation: the pulmonary reimplantation response

BACKGROUND

Although the development of noncardiogenic pulmonary edema or pulmonary reimplantation response (PRR) after lung transplantation has been well described, the incidence has not been established and the relationship of PRR to clinical risk factors has not been analyzed.

STUDY OBJECTIVES

(1) To describe the incidence of PRR in lung transplant recipients, (2) to identify the predictors of PRR, (3) to examine the correlation of suspected predictors with the severity of PRR, and (4) to evaluate the impact of PRR on morbidity and mortality of lung transplant recipients.

DESIGN

Retrospective review of clinical records and radiographic studies.

SETTING

Tertiary care referral center.

PATIENTS

Ninety-nine consecutive patients with end-stage lung disease undergoing lung transplantation between February 1990 and October 1995.

METHODS

Review of clinical records and postoperative chest radiographs of all lung transplant recipients to identify patients who experienced PRR. Chest radiographs of patients with PRR were graded for severity on a scale of 0 (none) to 5 (very severe). Demographic, pre- and perioperative factors were also evaluated along with short- and long-term survival of patients with PRR.

RESULTS

Fifty-six of 99 lung transplant recipients (57%) experienced PRR. The median ischemia time of patients with and without PRR was 168 and 180 min, respectively (p = 0.62). The incidence of PRR was 51% in patients without preoperative pulmonary hypertension, 78% in mild to moderate pulmonary hypertension, and 58% in patients with severe pulmonary hypertension (p = 0.10). Incidence and severity of PRR was similar in patients receiving right, left, or double-lung transplantation. Similarly, age and sex of the recipients and underlying lung disease did not affect the incidence or severity of PRR. The incidence and severity of PRR was higher in patients undergoing cardiopulmonary bypass during lung transplantation. Patients with PRR had prolonged duration of mechanical ventilation and ICU stay. Overall, PRR did not affect the survival of the patients. However, survival of female lung transplant recipients was significantly better than male recipients (median survival, 60 vs 21 months; p = 0.02).

CONCLUSIONS

Acute pulmonary edema or PRR occurs frequently (57%) after lung transplantation. In this series, PRR was not associated with a prolonged ischemia time, preoperative pulmonary hypertension, the type of lung transplant, underlying lung disease, or age or sex of recipients. However, use of cardiopulmonary bypass during surgery was associated with increased incidence and severity of PRR. Also, the development of PRR resulted in prolonged mechanical ventilation and a longer ICU stay, but did not affect survival. Female lung transplant recipients survived significantly longer than male recipients. The reason for this difference in survival is unclear.

Bronchoalveolar lavage in lung transplantation. State of the art

Fiberoptic bronchoscopy with bronchoalveolar lavage (BAL) has become a crucial tool in the management of lung transplant recipients. Detection of pulmonary infectious pathogens by culture, cytology, and histology of BAL, protected brush specimens, and transbronchial biopsies (TBB) is highly effective. Morphologic and phenotypological analyses of BAL cells may be suggestive for certain complications after lung transplantation. For interpretation of BAL findings, the natural course of BAL cell morphology and phenotypology after lung transplantation must be considered. During the first 3 months after pulmonary transplantation, elevated total cell count in BAL and neutrophilic alveolitis are common, representing the cellular response to graft injury and interaction of immunocompetent cells of donor and recipient origin. With increasing time after transplantation the CD4/CD8 ratio decreases due to lowered percentages of CD4 cells in BAL. During bacterial pneumonias, the cellular profile of BAL is characterized by a marked granulocytic alveolitis. Lymphocytic alveolitis with a decreased CD4/CD8 ratio is suggestive of acute rejection, but is also found in viral pneumonias and obliterative bronchiolitis. In the case of a combined lymphocytosis and neutrophilia without any evidence of infection, obliterative bronchiolitis should be considered. Functional analyses of BAL cells can give additional information about the immunologic status of the graft, even before histologic changes become evident but have not been established in routine transplant monitoring. However, functional studies suggest an important role of activated, alloreactive and donor-specific T lymphocytes in the pathogenesis of acute and chronic lung rejection. Investigations of soluble components in BAL have given further insight into the immunologic processes after lung transplantation. In this overview, the characteristics of BAL after lung transplantation will be summarized, and its relevance for the detection of pulmonary complications will be discussed.

Alveolar epithelial fluid transport capacity in reperfusion lung injury after lung transplantation

Reperfusion lung injury is an important cause of morbidity and mortality after orthotopic lung transplantation. The purpose of this study was to investigate the function of the alveolar epithelium in the setting of reperfusion lung injury. Simultaneous samples of pulmonary edema fluid and plasma were collected from eight patients with severe post-transplantation reperfusion edema. The edema fluid to plasma protein ratio was measured, an indicator of alveolar-capillary barrier permeability. The initial edema fluid to plasma protein ratio was > 0.75 in six of eight patients, confirming the presence of increased permeability of the alveolar-capillary barrier. Graft ischemic time was positively correlated with the degree of permeability (r = 0.77, p < 0.05). In four of six patients with serial samples, there was a high rate of alveolar fluid clearance (19 +/- 9%/h, mean +/- SD). Alveolar fluid clearance was calculated from serial samples in six patients. Intact alveolar fluid clearance correlated with less histologic injury, rapid resolution of hypoxemia, and more rapid resolution of radiographic infiltrates. The two patients with no net alveolar fluid clearance had persistent hypoxemia and more severe histologic injury. This study provides the first direct evidence that increased permeability to protein is the usual cause of reperfusion edema after lung transplantation, with longer ischemic times associated with greater permeability to protein in the transplanted lung. The high rates of alveolar fluid clearance indicate that the fluid transport capacity of the alveolar epithelium may be well preserved in the allograft despite reperfusion lung injury. The ability to reabsorb fluid from the alveolar space was a marker of less severe reperfusion injury, whereas the degree of alveolar-capillary barrier permeability to protein was not. Measurement of alveolar fluid clearance may be useful to assess the severity of reperfusion lung injury and to predict outcome when pulmonary edema develops after lung transplantation.

Transalveolar fluid absorption ability in rat lungs preserved with Euro-Collins solution and EP4 solution

BACKGROUND

Pulmonary reimplantation response, presenting lung edema, is a major obstacle of lung transplantation. Transalveolar fluid absorption mechanism, regulated by active transalveolar Na+ transport via Na+ channel and Na+-K+-ATPase, is considered to be essential for resolution of lung edema. We investigated the effect of lung preservation on this fluid transport mechanism.

METHODS

The rat lungs were flushed and preserved with either EP4 solution (EP4) or Euro-Collins solution (EC). First, we determined the basal transalveolar fluid movement by calculating alveolar fluid clearance (AFC) after pulmonary flushing, 24- and 72-hr preservation. Then, we assessed the effects of Na+ channel blocker, amiloride, and Na+-K+-ATPase inhibitor, ouabain, on AFC after 24-hr preservation. We further measured lung ATP content and Na+-K+-ATPase activity after 24-hr preservation to evaluate cellular metabolism and enzymatic activity during preservation.

RESULTS

We found that the lungs preserved with EC showed significantly lower AFC and less inhibitory effects of both blockers than with EP4 after 24-hr preservation. Na+-K+-ATPase activity was significantly lower with EC than with EP4, even though lung ATP content was not affected by preservation solution.

CONCLUSIONS

EP4 preservation provides a better environment for maintaining transalveolar fluid absorption mechanism than EC preservation. Therefore, lung preservation with EP4 may ensure more reliable ability in resolving pulmonary edema.

Primary graft failure following lung transplantation

STUDY OBJECTIVES

To determine the incidence of primary graft failure (PGF) following lung transplantation, assess possible risk factors, and characterize its effect on outcomes.

METHODS

Retrospective review of 100 consecutive patients undergoing lung transplantation at the University of Pennsylvania Medical Center. Fifteen patients meeting diagnostic criteria for PGF (PGF+ group) were compared with 85 patients without this complication (PGF- group).

RESULTS

The incidence of PGF was 15%. There was no significant difference in age, sex, underlying pulmonary disease, preoperative pulmonary artery systolic pressure, type of transplant, allograft ischemic times, use of cardiopulmonary bypass, or use of postoperative prostaglandin E1 infusion between the PGF+ and PGF- groups. Induction therapy with antilymphocyte globulin was used less frequently in the PGF+ group (p<0.005). Duration of mechanical ventilatory support was 36+/-43 days vs 4+/-6 days for the PGF+ and PGF- groups, respectively (p<0.0001). Hospital stay was significantly longer in the PGF+ group, averaging 75+/-105 days, compared with 27+/-38 days in the PGF group (p<0.005). One-year actuarial survival for the PGF+ group was only 40% compared with 69% for the PGF- group (p<0.005). Five of the six PGF+ survivors were ambulatory by 1 year; three were completely independent while two continued to require assistance with activities of daily living. Six-minute walk test distance among the ambulatory patients averaged 883+/-463 feet (range, 200 to 1,223 feet) compared with 1513+/-424 feet for the PGF- group (p<0.005). Among the subset of survivors who underwent single lung transplantation for COPD, the mean percent predicted FEV1 at 1 year was 43% for the PGF+ group and 55% for the PGF- groups, but this difference was not statistically significant.

CONCLUSIONS

PGF is a devastating postoperative complication, occurring in 15% of patients in the current series, and it is associated with a high mortality rate, lengthy hospitalization, and protracted and often compromised recovery among survivors.

Vascular distension and continued ventilation are protective in lung ischemia/reperfusion

Biophysical factors have been implicated in the development of pulmonary ischemia-reperfusion injury. In isolated rabbit lungs, the impact of vascular and alveolar distension, with and without alveolar oxygen supply, was investigated. With interruption of both perfusion (zero intravascular pressure) and ventilation, reperfusion after 120 min of warm ischemia resulted in transient pulmonary hypertension, with largely unchanged microvascular pressures, followed by a dramatic leakage response with approximately 10-fold increased capillary filtration coefficients (Kfc) and severe edema. Maintenance of vascular distension during ischemia (intravascular pressure of approximately 2 to 3 mm Hg) reduced the hypertension and fully suppressed the leakage. Employing ischemic periods of 180 and 240 min, ventilation of the lungs with 21 or 100% oxygen > ventilation with nitrogen during perfusion stop, but not static anoxic inflation, further enhanced the protective effect of vascular distension. At optimal biophysical support (vascular distension and ongoing normoxic ventilation), even 240 min of warm ischemia was tolerated with only moderate Kfc increase. We conclude that biophysical factors exert marked influence on pulmonary ischemia-reperfusion injury. Maintenance of vascular distension possesses strong protective potency, further enhanced by continued ventilation and alveolar oxygen supply during ischemia. These results may have important implications for organ preservation in lung transplantation.

Prophylaxis post-transplant. The role of monitoring surveillance bronchoscopy and antimicrobials

One of the key areas of successful organ transplantation is the prompt recognition and treatment of problems that otherwise can progress rapidly, leading to morbidity and mortality. Surveillance and prophylaxis are essential in the field of transplant medicine.

Perioperative management in lung transplantation

Despite the multitude of potential complications that may be encountered during the early post-transplant period, the majority of transplant recipients experience a smooth transition from postoperative intensive care, to step-down unit, to the regular medical floor, and, ultimately, to their home within 10 to 14 days without any significant unexpected events. The likelihood of serious complications can be greatly reduced through careful recipient selection, impeccable donor management, and the cooperative efforts of surgeons, pulmonologists, nurse specialists, and the numerous experienced consultants required for a successful transplant program. Although many unique facets contribute to the complexity of lung transplant patient care, attention to the details of high-quality general postsurgical care will yield excellent results.

Perioperative anaesthetic considerations for patients undergoing lung transplantation

PURPOSE

Five thousand, two hundred and eight lung transplants were performed worldwide before April, 1996. This review will discuss lung transplantation from an historical perspective, its indications, donor and recipient selection criteria, donor lung preparation, surgical considerations, perioperative anaesthetic management, and associated morbidity and mortality.

SOURCE

Recent literature on perioperative anaesthetic management of lung transplantation and experience from international centres including the Toronto Lung Transplant Group and the St. Louis Lung Transplant Group.

PRINCIPAL FINDINGS

Lung transplantation comprises of a family of operations, including single lung transplant, bilateral single lung transplant, lobar transplant and block heart-lung transplant. Improved donor lung preservation techniques have increased the duration of cold ischaemic time. The advent of bilateral single lung transplant has decreased the requirement for cardiopulmonary bypass, and airway complications have been reduced by adoption of the telescoping bronchial anastomoses. Advances in perioperative monitoring (including transoesophageal echocardiography), pulmonary vasodilators (e.g., nitric oxide and prostaglandin E1), cardiopulmonary bypass and ventilatory management, and a better understanding of the pathophysiological processes during the procedure have improved perioperative anaesthetic management. Also, advances in broad spectrum antibiotics and immunosuppressant drugs have improved the outcome by better management of the complications of infection and rejection.

CONCLUSION

Lung transplantation improves the quality of life with marginal improvement in life expectancy of the recipients. It is an expensive procedure requiring continued resources for long term management of these patients.

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

Further examination of the parameters of oxidative stress, perioperative changes in the vasoregulatory mechanisms of the pulmonary circulation, and characterisation of the endothelial insult that probably occurs in all patients undergoing lung resection is necessary if the operative conditions under which lung surgery is carried out are to be optimised. Perhaps, then, more insight might be gained into how to improve preservation of lungs for transplantation and how to protect the lung from significant injury following resection.