Abnormalities of pulmonary diffusion capacity in long-term survivors after kidney transplantation

Assessment of respiratory function in children after kidney transplantation

BACKGROUND

Severe respiratory complications following kidney transplantation have been reported, yet remain poorly understood in the pediatric population. This study aimed to document respiratory disease in this population.

METHODS

At annual follow-ups, patients completed a respiratory symptoms questionnaire and underwent pulmonary function tests (PFTs). We defined respiratory disease in children when they had clinical disorders and/or PFT abnormalities.

RESULTS

Among 236 children included, 110 (41%) exhibited respiratory involvement: 59 (53%) had only clinical disorders, 38 (35%) had only PFT abnormalities, and 13 (12%) had both. Of those with PFT abnormalities, 15 (7%) had obstructive impairment, 12 (6%) had restrictive impairment, and 30 (24%) showed decreased lung diffusion capacity for carbon monoxide (DLCO)/transfer coefficient for carbon monoxide (KCO). In the multivariate analysis, being over 3.5 years of age at the time of transplantation was associated with a reduced risk of respiratory involvement (OR 0.30, CI [0.14; 0.63], p = 0.002), such as induction with basiliximab (OR 0.39, CI [0.17; 0.90], p = 0.03). Conversely, history of immune deficiency, male gender, positive PCR for BK virus and diastolic hypertension were associated with an increased risk (OR 5.96, CI [2.15; 16.51], p = 0.0006, OR 1.97, CI [1.03; 3.77], p = 0.04, OR 3.77, CI [1.14; 12.52], p = 0.03 and OR 2.21, CI [1.13; 4.32], p = 0.02, respectively). Bronchial lesions, such as bronchiectasis, were predominantly observed on tomography.

CONCLUSIONS

Given the risk of irreversible lung damage, we recommend systematic clinical and functional respiratory monitoring in case of respiratory symptoms, recurrent lower respiratory tract infections, and risk factors in their follow-up.

Kidney Transplant Recipients Show Limited Lung Diffusion Capacity but Similar Hydrogen Peroxide Exhalation as Healthy Matched Volunteers: A Pilot Study

Patients with end-stage chronic kidney disease show higher systemic oxidative stress and exhale more hydrogen peroxide (H2O2) than healthy controls. Kidney transplantation reduces oxidative stress and H2O2 production by blood polymorphonuclear leukocytes (PMNs). Kidney transplant recipients (KTRs) may be predisposed to an impairment of lung diffusing capacity due to chronic inflammation. Lung function and H2O2 concentration in the exhaled breath condensate (EBC) were compared in 20 KTRs with stable allograft function to 20 healthy matched controls. Serum interleukin eight (IL-8) and C-reactive protein (CRP), blood cell counts, and spirometry parameters did not differ between groups. However, KTRs showed lower total lung diffusing capacity for carbon monoxide, corrected for hemoglobin concentration (TLCOc), in comparison to healthy controls (92.1 ± 11.5% vs. 102.3 ± 11.9% of predicted, p = 0.009), but similar EBC H2O2 concentration (1.63 ± 0.52 vs. 1.77 ± 0.50 µmol/L, p = 0.30). The modality of pre-transplant renal replacement therapy had no effect on TLCOc and EBC H2O2. TLCOc did not correlate with time after transplantation. In this study, TLCOc was less reduced in KTRs in comparison to previous reports. We suggest this fact and the non-elevated H2O2 exhalation exhibited by KTRs, may result perhaps from the evolution of the immunosuppressive therapy.

Extracorporeal organ support and the kidney

The concept of extracorporeal organ support (ECOS) encompasses kidney, respiratory, cardiac and hepatic support. In an era of increasing incidence and survival of patients with single or multiple organ failure, knowledge on both multiorgan crosstalk and the physiopathological consequences of extracorporeal organ support have become increasingly important. Immerse within the cross-talk of multiple organ failure (MOF), Acute kidney injury (AKI) may be a part of the clinical presentation in patients undergoing ECOS, either as a concurrent clinical issue since the very start of ECOS or as a de novo event at any point in the clinical course. At any point during the clinical course of a patient with single or multiple organ failure undergoing ECOS, renal function may improve or deteriorate, as a result of the interaction of multiple factors, including multiorgan crosstalk and physiological consequences of ECOS. Common physiopathological ways in which ECOS may influence renal function includes: 1) multiorgan crosstalk (preexisting or de-novo 2)Hemodynamic changes and 3) ECOS-associated coagulation abnormalities and 3) Also, cytokine profile switch, neurohumoral changes and toxins clearance may contribute to the expected physiological changes related to ECOS. The main objective of this review is to summarize the described mechanisms influencing the renal function during the course of ECOS, including renal replacement therapy, extracorporeal membrane oxygenation/carbon dioxide removal and albumin dialysis.

Duration of hemodialysis associated with cardio-respiratory dysfunction and breathlessness: a multicenter study

Background

Patients with hemodialysis suffer with protein-energy wasting and uremic myopathy lead to lack of physical activity and poor functional performance. However, ventilation abnormality in patients undergone hemodialysis remains controversial regarding the respiratory impairment. Therefore, the study aimed to determine the effect of duration of dialysis on respiratory function.

Methods

A multicenter study with cross-sectional study was designed in four hemodialysis outpatient clinics. Respiratory muscle strength (i.e., maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP)) pulmonary function test (i.e., forced vital capacity (FVC), forced expiratory volume in one second (FEV₁) and FEV₁/FVC ratio), functional capacity (6-minute walk test) and sensation of breathlessness were assessed prior to dialysis.

Results

A total of 100 hemodialysis patients were recruited with 38 females and 62 males. An average of duration of hemodialysis was 5.93± 4.96 years. Decreased MIP values, FEV₁ values, FVC values, %FEV₁ and %FVC were noted in patients with long duration of dialysis (defined as ≥ 5 years of dialysis) compared to those with short duration of dialysis (p_s < .05). In addition, increased sensation of breathlessness was observed in patients with long duration of dialysis (p < .05). Furthermore, participants with long duration of dialysis had an increased risk of ventilatory restriction (OR 6.093, p = .007).

Reference Values for Pulmonary Single-Breath Diffusing Capacity - Results of the "Study of Health in Pomerania"

OBJECTIVES

 The assessment of pulmonary single-breath diffusing capacity is a frequently performed diagnostic procedure and considered as an important tool in medical surveillance examinations of pulmonary diseases.The aim of this study was to establish reference equations for pulmonary single-breath diffusing capacity parameters in a representative adult-population across a wide age range and to compare the normative values from this sample with previous ones.

METHODS

 Diffusing capacity measurement was carried out in 3566 participants (1811 males) of a cross-sectional, population-based survey ("Study of Health in Pomerania - SHIP").

RESULTS

 Individuals with cardiopulmonary disorders and current smoking habits were excluded, resulting in 1786 healthy individuals (923 males), aged 20 - 84 years. Prediction equations for both sexes were established by quantile regression analyses, taking into consideration the influence of age, height, weight and former smoking.

CONCLUSION

 The study provides a novel set of prediction equations for pulmonary single-breath diffusing capacity in an adult Caucasian population. The results are comparable to previously reported equations, underline their importance and draw attention to the need for up-to-date reference equations that adequately take into account both the subjects' origin, age, anthropometric characteristics and the equipment used.

Management of Chronic Kidney Disease Patients in the Intensive Care Unit: Mixing Acute and Chronic Illness

Patients with chronic kidney disease (CKD) are at high risk for developing critical illness and for admission to intensive care units (ICU). 'Critically ill CKD patients' frequently develop an acute worsening of renal function (i.e. acute-on-chronic, AoC) that contributes to long-term kidney dysfunction, potentially leading to end-stage kidney disease (ESKD). An integrated multidisciplinary effort is thus necessary to adequately manage the multi-organ damage of those kidney patients and contemporaneously reduce the progression of kidney dysfunction when they are critically ill. The aim of this review is to describe (1) the pathophysiological mechanisms underlying the development of AoC kidney dysfunction and its role in the progression toward ESKD; (2) the most common clinical presentations of critical illness among CKD/ESKD patients; and (3) the continuum of care for CKD/ESKD patients from maintenance hemodialysis/peritoneal dialysis to acute renal replacement therapy performed in ICU and, vice-versa, for AoC patients who develop ESKD.

Pulmonary Function in Patients with End-Stage Renal Disease: Effects of Hemodialysis and Fluid Overload

Background

Respiratory system disorders are one of the most prevalent complications in end-stage renal disease patients on hemodialysis. However, the pathogenesis of impaired pulmonary functions has not been completely elucidated in these patients. We designed a study to investigate acute effects of hemodialysis treatment on spirometry parameters, focusing on the relationship between pulmonary function and fluid status in hemodialysis patients.

Material/Methods

We enrolled 54 hemodialysis patients in this study. Multifrequency bioimpedance analysis (BIA) was used to assess fluid status before and 30 min after the midweek of hemodialysis (HD). Overhydration (OH)/extracellular water (ECW)% ratio was used as an indicator of fluid status. Fluid overload was defined as OH/ECW ≥7%. Spirometry was performed before and after hemodialysis.

Results

Forced vital capacity (FVC), FVC%, and forced expiratory volume in the first second (FEV1) levels were significantly increased after hemodialysis. FVC, FVC%, FEV1, FEV1%, mean forced expiratory flow between 25% and 75% of the FVC (FEF25–75), FEF25–75%, peak expiratory flow rate (PEFR), and PEFR% were significantly lower in patients with fluid overload than in those without. OH/ECW ratio was negatively correlated with FVC, FVC%, FEV1, FEV1%, FEF25–75, FEF25–75%, PEFR, and PEFR%. Stepwise multiple regression analysis revealed that male sex and increased ultrafiltration volume were independently associated with higher FVC, whereas increased age and OH/ECW ratio were independently associated with lower FVC.

Conclusions

Fluid overload is closely associated with restrictive and obstructive respiratory abnormalities in HD patients. In addition, hemodialysis has a beneficial effect on pulmonary function tests, which may be due to reduction of volume overload.

Cardio-Pulmonary-Renal Interactions: A Multidisciplinary Approach

Over the past decade, science has greatly advanced our understanding of interdependent feedback mechanisms involving the heart, lung, and kidney. Organ injury is the consequence of maladaptive neurohormonal activation, oxidative stress, abnormal immune cell signaling, and a host of other mechanisms that precipitate adverse functional and structural changes. The presentation of interorgan crosstalk may include an acute, chronic, or acute on chronic timeframe. We review the current, state-of-the-art understanding of cardio-pulmonary-renal interactions and their related pathophysiology, perpetuating nature, and cycles of increased susceptibility and reciprocal progression. To this end, we present a multidisciplinary approach to frame the diverse spectrum of published observations on the topic. Assessment of organ functional reserve and use of biomarkers are valuable clinical strategies to screen and detect disease, assist in diagnosis, assess prognosis, and predict recovery or progression to chronic disease.

Long-term successful outcomes from kidney transplantation after lung and heart-lung transplantation

BACKGROUND

Renal dysfunction is common after lung and heart-lung transplantation (Tx), and it limits the recipient's survival and quality of life. This study analyzed the outcomes of simultaneous and late kidney Tx following lung and heart-lung Tx.

METHODS

From a single-center retrospective chart review of 1031 lung and heart-lung Tx recipients, we identified 13 simultaneous or late kidney Tx cases in 12 patients.

RESULTS

Three patients underwent simultaneous deceased donor lung and kidney Tx. Eight patients underwent lung and heart-lung Tx, followed by nine living donor kidney Tx (including one ABO-incompatible Tx). One additional patient underwent a late deceased donor kidney Tx following heart-lung Tx. The median time from lung and heart-lung Tx to later kidney Tx was 127 (interquartile range [IQR], 23 to 263) months. Three patients died, 1 of sepsis, 1 of multiple organ failure, and 1 of transplant coronary disease. At a median follow-up of 33 (IQR, 10 to 51) months, 9 patients are alive and well. Eight patients required dialysis before kidney Tx for a median time of 14 months (IQR, 5 to 49). Kidney graft loss occurred in 1 patient at 51 months. After kidney Tx, dialysis was necessary in association with acute allograft dysfunction in 2 patients. No acute kidney rejection has been detected in any patient. Treatable acute lung rejection was seen in 1 patient. Well-preserved pulmonary function was noted in recipients of late kidney Tx.

CONCLUSIONS

Simultaneous kidney Tx and late deceased donor kidney Tx have challenges in the setting of lung Tx. By contrast, late living related kidney Tx after lung Tx is associated with excellent long-term survival and acceptable kidney and lung allograft function.

Subclinical interstitial lung abnormalities in stable renal allograft recipients in the era of modern immunosuppression

BACKGROUND

Interstitial lung abnormalities have been detected in up to 24% of kidney transplant patients receiving traditional immunosuppressive therapies (eg, cyclosporine, azathioprine); they usually occur early after transplantation and tend to resolve over time. Newer immunosuppressants such as mycophenolic acid and, particularly, mammalian target of rapamycin (mTOR) inhibitors (eg, sirolimus) may cause significant lung toxicity. However, the prevalence and severity of interstitial lung lesions in long-term, stable kidney transplant patients receiving either traditional or newer immunosuppressants is not known.

METHODS

We conducted a prospective, cross-sectional study examining high-resolution lung computed tomography (CT) scans in 63 stable kidney transplant recipients whose immunosuppressive therapy had remained unchanged for over 24 months. We compared CT findings of patients taking newer (mycophenolic acid and mTOR inhibitors) and traditional (calcineurin inhibitors and azathioprine) immunosuppressive drugs.

RESULTS

Interstitial lung alterations were observed in only 3/63 patients (4.8%); the prevalence was 11.5% (3/26) versus 0% (0/37) among the newer versus traditional immunosuppressive therapy groups, respectively (P = .065). The CT patterns were usual interstitial pneumonia and nonspecific interstitial pneumonia-like. The median time between transplant and CT was 49 months in the three patients with CT alterations and 95 months in the remaining 23 patients on newer immunosuppressants. It was 75 months for all patients on newer immunosuppressive drugs and 133 months for those on traditional therapies (P = .0015). A follow-up CT, performed in 2/3 patients with interstitial abnormalities, showed that the lesions were stable in one, while they had disappeared in the other.

CONCLUSIONS

Interstitial lung abnormalities are infrequent and mild in stable kidney transplant patients treated with newer as well as traditional immunosuppressive drugs. As such abnormalities were detected in patients screened earlier after transplantation, the time since transplantation rather than the drug type is probably the major determinant.

Lung transplantation and lung volume reduction surgery

Since the publication of the last edition of the Handbook of Physiology, lung transplantation has become widely available, via specialized centers, for a variety of end-stage lung diseases. Lung volume reduction surgery, a procedure for emphysema first conceptualized in the 1950s, electrified the pulmonary medicine community when it was rediscovered in the 1990s. In parallel with their technical and clinical refinement, extensive investigation has explored the unique physiology of these procedures. In the case of lung transplantation, relevant issues include the discrepant mechanical function of the donor lungs and recipient thorax, the effects of surgical denervation, acute and chronic rejection, respiratory, chest wall, and limb muscle function, and response to exercise. For lung volume reduction surgery, there have been new insights into the counterintuitive observation that lung function in severe emphysema can be improved by resecting the most diseased portions of the lungs. For both procedures, insights from physiology have fed back to clinicians to refine patient selection and to scientists to design clinical trials. This section will first provide an overview of the clinical aspects of these procedures, including patient selection, surgical techniques, complications, and outcomes. It then reviews the extensive data on lung and muscle function following transplantation and its complications. Finally, it reviews the insights from the last 15 years on the mechanisms whereby removal of lung from an emphysema patient can improve the function of the lung left behind.

Changes in pulmonary function in patients with chronic renal failure after successful renal transplantation

OBJECTIVE

Pulmonary function abnormalities have been described in patients with chronic renal failure. There are very few longitudinal studies showing the effect of renal transplantation on pulmonary function. We aimed to study the effects of renal failure on pulmonary functions and to observe the changes following successful renal transplantation.

MATERIAL AND METHODS

Patients with end-stage renal failure (n=25) of various etiologies who presented to the renal transplant unit of a teaching hospital were included in this prospective, longitudinal study. Patients with a prior history of pulmonary disease and chronic smokers were excluded. Pulmonary function tests were performed and blood gases evaluated before and 6 months after successful renal transplantation.

RESULTS

Most patients showed pulmonary function abnormalities which improved significantly after transplantation. The mean vital capacity increased from 2.89 (95% CI 2.63-3.15) l pre-transplantation to 3.32 (95% CI 3.09-3.54) l post-transplantation (p<0.001), indicating that subjects had a restrictive pulmonary function defect which improved after transplantation. The large airways were normal, as evidenced by normal forced expiratory volume in the first second:forced vital capacity ratios. There was significant small airways dysfunction, as shown by low maximal mid-expiratory flow rates, which tended to improve after renal transplantation (p=0.013). There was also a highly significant (p<0.001) improvement in maximal voluntary ventilation (MVV) after transplantation. The MVV test is a composite test which measures all aspects of pulmonary function, including respiratory muscle strength. However, not all patients achieved normal pulmonary function due to uremia-induced irreversible pre-transplantation changes.

CONCLUSION

Pulmonary function abnormalities are common in patients with chronic renal failure but can be significantly ameliorated following successful renal transplantation.

Acute effects of hemodialysis on lung function in patients with end-stage renal disease

Impaired lung function in hemodialysis patients may be caused by an underlying pulmonary disease; however, the impact of uremia and the effects of dialysis treatment are not well understood. Our investigation aimed to characterize the acute effects of bicarbonate hemodialysis using membranes differing in biocompatibility on various parameters of lung function in unselected uremic patients maintained on regular hemodialysis. Fourteen clinically stable hemodialysis patients without acute lung disease were included in the study. Restrictive lung disease was present in eight of 14 cases and obstructive lung disease in one patient. A cellulose dialyzer membrane and a synthetic high-flux dialyzer membrane were each tested twice (two sessions one week apart). Spirometry (VCmax, FEV1, FEF(25-75%), PEF) was carried out before and after hemodialysis. Resistance was determined with the interrupter technique and with the impulse oscillation system (R5Hz, R20Hz) before, during and after hemodialysis. Our comparative investigation of two dialyzer membranes found that bioincompatibility of dialysis had no acute adverse effects on lung function in our heterogeneous population of dialysis patients. None of our patients experienced bronchoconstriction or aggravation of obstructive lung disease as a result of poor biocompatibility of the dialyzer membrane. Spirometric data and resistance measurements by two different methods showed no relevant changes during the dialysis procedure. There was no correlation between lung function parameters and interdialytic changes in body weight or duration on hemodialysis. Regardless of the membrane used, the hemodialysis procedure does not acutely affect lung function in uremic patients on maintenance hemodialysis. Hemodialysis is a safe procedure even in uremic patients with pre-existing lung disease.

Noninfectious Pulmonary Complications of Liver, Heart, and Kidney Transplantation

Because of their chronically immunosuppressed status, solid organ transplant recipients are continually at risk for infectious pulmonary complications. In addition, however, a number of noninfectious pulmonary complications plague the transplant recipient. These complications arise because of numerous factors, including the underlying conditions that preceded transplantation, the transplant surgery itself, and toxicity of post-transplantation medications. This article focuses on noninfectious pulmonary complications in the three largest recipient populations: liver, kidney, and heart.

The Effect of Renal Transplantation on Pulmonary Function and Respiratory Muscle Strength in Patients With End-Stage Renal Disease

Pulmonary function and respiratory muscle strength was assessed in 29 hemodialysis patients who underwent successful renal transplantation. These tests were performed 7 days prior to transplantation, 30 days following transplantation, and 90 days posttransplantation. Patients with end-stage renal disease showed dyspnea, a restrictive defect in pulmonary function, respiratory muscle weakness, and hypoxia. Following transplantation the dyspnea improved and mechanical indices of respiratory muscle function and lung volume improved. In conclusion transplantation resulted in a significant improvement in lung and respiratory muscle function.