Impact of hemodialysis on dyspnea and lung function in end stage kidney disease patients

Exercise Improves Respiratory Function, Body Fluid and Nitric Oxide in Hemodialysis Patients

Emerging evidence suggests that resistance training (RT) can mitigate respiratory muscle weakness in hemodialysis (HD) patients. However, the underlying mechanisms responsible for these beneficial effects remain unclear. The purpose of this study was to assess the impact of periodized RT on respiratory muscle strength and its relationship with handgrip strength (HGS), fat-free mass (FFM), nitric oxide (NO), and interdialytic weight gain (IWG) in HD patients. Thirty-three patients were randomly assigned to two groups: control (CTL; n=18) and RT (n=15). The RT group did not perform any additional exercise training specific to the respiratory tract. Maximal inspiratory (MIP) and expiratory (MEP) pressures, peak expiratory flow (PEF), HGS, FFM, NO, and IWG were measured before and after the intervention period. Participants in the RT group engaged in a 24-week RT program, three times per week. RT resulted in significant improvements in MIP, MEP, PEF, as well as enhancements in HGS, FFM, NO, and IWG (p<0.05). Notably, inverse correlations were observed between MIP (r=-0.37, p=0.03) and PEF (r=-0.4, p=0.02) with IWG. Thus, the amelioration of HGS and FFM coincided with a reduction in respiratory muscle weakness among HD patients. Decreased IWG and increased circulating NO are plausible mechanisms contributing to these improvements.

Mathematical modelling of bicarbonate supplementation and acid-base chemistry in kidney failure patients on hemodialysis

Acid-base regulation by the kidneys is largely missing in end-stage renal disease patients undergoing hemodialysis (HD). Bicarbonate is added to the dialysis fluid during HD to replenish the buffers in the body and neutralize interdialytic acid accumulation. Predicting HD outcomes with mathematical models can help select the optimal patient-specific dialysate composition, but the kinetics of bicarbonate are difficult to quantify, because of the many factors involved in the regulation of the bicarbonate buffer in bodily fluids. We implemented a mathematical model of dissolved CO2 and bicarbonate transport that describes the changes in acid-base equilibrium induced by HD to assess the kinetics of bicarbonate, dissolved CO2, and other buffers not only in plasma but also in erythrocytes, interstitial fluid, and tissue cells; the model also includes respiratory control over the partial pressures of CO2 and oxygen. Clinical data were used to fit the model and identify missing parameters used in theoretical simulations. Our results demonstrate the feasibility of the model in describing the changes to acid-base homeostasis typical of HD, and highlight the importance of respiratory regulation during HD.

Six-minute walk test may be a reliable predictor of peak oxygen uptake in patients undergoing hemodialysis

Background

Cardiorespiratory fitness seems to play an important role in the general health of patients undergoing hemodialysis (HD). However, the prediction of peak oxygen uptake (V̇O2peak) in a clinical setting is not widely adopted for these patients.

Objectives

Evaluate the agreement and reliability between directly and indirectly V̇O2peak measurements in patients undergoing HD.

Methods

This is a cross-sectional study with patients undergoing HD that performed a cardiopulmonary exercise test (CPET) with 5/10 watts incremental load in each minute using a cycle ergometry to directly evaluate the V̇O2peak, and the 6-min walk test (6MWT) in a 30-m corridor to indirect measures it. Both tests were performed on a midweek non-dialysis day. Bland–Altman analysis of agreement limits was used with direct and indirect V̇O2peak values. Intraclass correlation coefficient (ICC) and Cronbach’s Alpha was used to evaluate the reproducibility and reliability between direct and indirect V̇O2peak values.

Results

Twenty-six patients (54.4 ± 14.5 years, 53.8% of male) were evaluated. The V̇O2peak direct mean obtained through CPET was 15.91 ± 5.26 (ml/kg/min), while the indirect mean obtained through 6MWT was V̇O2peak of 14.89 ± 4.21 (ml/kg/min). There was a strong positive correlation between both V̇O2peak values (r = 0.734; p < 0.001). The Bland–Altman analysis demonstrated that the methods agreed with each other (p = 0.103). Also, the ICC (0.829) and Cronbach's Alpha (0.846) showed excellent reproducibility and reliability.

Conclusions

6MWT is a reliable tool for estimating V̇O2peak in patients undergoing HD.

Hypoxia during maintenance hemodialysis-the critical role of pH

Background

The impact and management of subclinical hypoxia during hemodialysis is a significant medical challenge. As key determinants of O₂ availability and delivery, proposed mechanisms contributing to hypoxia include ischemia, alkalemia and pulmonary leukocyte sequestration. However, no study has comprehensively investigated and compared these interrelated mechanisms throughout a typical hemodialysis treatment week. This study aimed to comprehensively assess the physiological mechanisms that contribute to hypoxia during hemodialysis.

Methods

In 76 patients, we measured arterial blood gases and pH at four time-points during hemodialysis (start, 15 min, 60 min, end) over the course of a standard treatment week. For the mid-week hemodialysis session, we additionally measured central hemodynamics (non-invasive cardiac output monitoring) and white blood cell count.

Results

Linear regression modelling identified changes in pH, but not central hemodynamics or white blood cell count, to be predictive of changes in PaO₂ throughout hemodialysis (e.g. at 60 min, β standardized coefficient pH = 0.45, model R² = 0.25, P < .001). Alkalemia, hypokalemia, decreased calcium and increased hemoglobin-O₂ affinity (leftward shift in the oxyhemoglobin dissociation curve) were evident at the end of hemodialysis. pH and hemoglobin-O₂ affinity at the start of hemodialysis increased incrementally over the course of a standard treatment week.

Conclusion

These data highlight the important role of pH in regulating O₂ availability and delivery during hemodialysis. Findings support routine pH monitoring and personalized dialysate bicarbonate prescription to mitigate the significant risk of alkalemia and subclinical hypoxia.

The impact of hydration status and fluid distribution on pulmonary function in COPD patients

Chronic Obstructive Pulmonary Disease (COPD) patients have alterations in body composition. Bioelectrical impedance analysis (BIA) evaluates body composition, hydration status, and fluid distribution. Subjects with fluid disturbances have been found to have lower FEV1, respiratory muscle strength, and poor prognosis. We aimed to evaluate the effect of hydration status and fluid distribution on pulmonary function in COPD patients. A cross-sectional study, 180 patients with a confirmed diagnosis of COPD were included. Patients with asthma, advanced renal or liver disease, acute HF, exacerbation of COPD, or pacemakers were excluded. Hydration status variables (TBW, ECW, ICW) and disturbance of fluid distribution [impedance ratio (IR) > 0.84 and phase angle (PhA)] were evaluated by BIA. Pulmonary function was assessed by spirometry. The mean population age was 71.55 ± 8.94 years; 55% were men. Subjects were divided into two groups according to the IR ≥ 0.84 or < 0.84. The group with higher IR ≥ 0.84 had lower FEV1, FVC, FEV1/FVC, DLCO and, PhA compared to those with IR < 0.84. After adjusting for confounding variables TBW, ECW, IR ≥ 0.84, PhA, and resistance/height increase were associated with decreased FEV1. In the same way, with IR ≥ 0.84, edema index ≥ 0.48, trunk and abdominal IR were negatively associated with FVC, and PhA had a positive association with FVC. Fluid distribution, especially IR and PhA, could be a useful parameter for predicting pulmonary function in COPD patients.

Intradialytic periodized exercise improves cardiopulmonary fitness and respiratory function: A randomized controlled trial

BACKGROUND

Chronic kidney disease (CKD) is a factor that predisposes to gradual physical deconditioning from its early stages leading to cardiorespiratory fitness and musculoskeletal system impairment. We evaluated the effects of combined and periodized intradialytic exercise training on cardiopulmonary fitness and respiratory function in HD subjects.

METHODS

A randomized controlled trial with HD subjects was allocated into two groups: exercise group (EXG) and usual care group (UCG). EXG performed a 12-week combined and periodized intradialytic training. UCG maintained the HD routine.

RESULTS

Thirty-nine HD subjects were analyzed (EXG = 20; UCG = 19). The EXG in comparison with the UCG showed improvements in peak oxygen consumption (Δ3.1[0.4-5.5] vs. -0.2[-2.0-1.5] ml/kg/min; p = 0.003), forced expiratory volume in the first second (Δ0.1[-0.0-0.1] vs. -0.0[-0.1-0.0] L; p = 0.022), forced vital capacity (Δ0.1[0.0-0.2] vs. -0.1[-0.2-0.0] L; p = 0.005), peak expiratory flow (Δ0.4[-0.7-1.2] vs. -0.1[-0.5-0.2] L; p = 0.046), and maximal inspiratory pressure (Δ7.35[-8.5-17.5] vs. -4.0[-18.0-12.0] cmH₂ O; p = 0.028). The EXG, different from the UCG, did not worsen the maximal expiratory pressure (Δ0.1[-8.8-7.5] vs. -2.5[-15.0-9.0] cmH₂ O; p = 0.036). Besides, EXG showed a significant improvement in quadriceps strength (32.05 ± 10.61 vs. 33.35 ± 11.62 kg; p = 0.042).

CONCLUSIONS

The combined and periodized intradialytic exercise training improved cardiopulmonary fitness, respiratory function, inspiratory muscle strength, and quadriceps strength, beyond maintaining the expiratory muscle strength in HD subjects.

Impact of inspiratory muscle training on diaphragmatic mobility and arterial blood gases in patients undergoing haemodialysis

Background/aims

Impairment of respiratory muscle function is common in patients with chronic kidney disease undergoing haemodialysis, and is manifested by decreased oxygenation and physical function. The purpose of this study was to analyse the impact of training with incentive spirometer on mobility of the diaphragm, arterial blood gases and functional capacity in patients with chronic kidney disease undergoing haemodialysis.

Methods

A pre–post research design was implemented. A total of 30 patients undergoing haemodialysis for chronic kidney disease received incentive spirometer training intradialysis three sessions a week for 8 weeks. Outcome measures were the amount of diaphragmatic mobility measured by ultrasonography, the levels of arterial partial pressure of oxygen, arterial partial pressure of carbon dioxide, oxygen saturation percentages and the distance walked in 6 minutes.

Results

Significant improvement from pre-treatment to post-treatment measurements occurred in all outcome measures, with P<0.05.

Conclusions

Incentive spirometer training should be recommended to be a part of daily routine of patients with chronic kidney disease who are undergoing haemodialysis to decrease respiratory and physical function impairments.

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).

Is the peripheral muscle weakness a limitation to exercise on chronic kidney disease?

Abstract Introduction: Chronic kidney disease (CKD) is a global public health problem with systemic repercussions, compromising muscle function and making patients less exercise tolerant. Objective: To verify the contribution of peripheral muscle strength in the exercise capacity of patients in hemodialysis (HD), as well as to compare peripheral muscle strength and exercise capacity between renal patients and healthy individuals. Method: 50 patients with chronic kidney disease (CKD) who performed HD and 13 healthy subjects underwent anthropometric evaluation, evaluation of peripheral muscle strength, pulmonary function test and exercise capacity assessment. Results: Simple linear regression indicated that the peripheral muscle strength contributed 41.4% to the distance walked in the six-minute walk test (R2 0.414; p < 0.001), showing that for every 1 Kgf reduced in the right lower limb the patient it stops walking 0.5m while for every 1 Kgf reduced in the lower left limb the patient stops walking 0.8m. In addition, it was observed that patients with CKD had a reduction in right lower limb muscle strength (129.44 ± 48.05 vs. 169.36 ± 44.30, p = 0.002), left (136.12 ± 52, 08 vs 168.40 ± 43.35, p = 0.01) and exercise capacity (421.20 ± 98.07 vs. 611.28 ± 80.91, p < 0.001) when compared to healthy pairs. Conclusion: Peripheral muscle weakness is an important limiting factor for exercise in CKD and patients on HD experience a decline in peripheral muscle strength and exercise capacity when compared to healthy individuals.

Relationship between handgrip strength and pulmonary capacity in patients on hemodialysis

Abstract Introduction: Chronic kidney disease (CKD) is defined as loss of kidney function, but its progression leads to systemic changes that compromise the quality of life of patients on dialysis. As such, the decline in lung capacity in this population may be one of the factors related to reduced peripheral muscle strength. Objective: Assess the relationship between handgrip strength (HGS), pulmonary function and respiratory muscle strength in patients with CKD on hemodialysis. Method: Thirty patients with CKD were assessed in terms of anthropometric data, pulmonary function, respiratory muscle strength and HGS. Results: A moderate association was observed between HGS and the variables forced vital capacity (r=0.54; p=0.002), maximum voluntary ventilation (r=0.51; p=0.004) and maximum expiratory pressure (r=0.59; p=0.001), and a weak association with forced expiratory volume in 1 second (FEV1) (r=0.46; p=0.009) and maximum inspiratory pressure (r=0.38; p=0.03). Additionally, about 67% of the sample (n=20) exhibited some degree of restrictive ventilatory defect in the pulmonary function test. With respect to muscle strength, 40% of the sample (n=12) displayed below-normal handgrip strength, as well as low mean MIP and MEP. Conclusion: Decreased lung capacity may be related to a decline in HGS in patients with chronic kidney disease on hemodialysis. Thus, therapeutic strategies aimed at lung expansion and respiratory muscle training may contribute to facilitating and favoring rehabilitation in this population.

Effect of parathyroid hormone levels on the functional capacity and pulmonary function of patients on dialysis

Abstract Introduction: Chronic kidney disease is characterized as the gradual loss of kidney function, with patients on dialysis experiencing a decline in functional capacity and pulmonary function. One of the non-traditional risk factors is parathyroid hormone (PTH), which influences metabolism and the status of the disease. Objective: Assess the effect of parathyroid hormone levels on functional capacity and pulmonary function in patients on dialysis. Method: Cross-sectional study with hemodynamically stable dialysis patients of both sexes, aged 18 to 59 years, who did not gain more than 2.5kg between dialysis sessions. Two groups were created according to PTH blood levels: PTH (A), with values outside the normal range, and PTH (C), who exhibited normal levels of the hormone. Pulmonary function (PF) was assessed by spirometry and functional capacity (FC) via the six-minute walk test (6MWT). Results: The PTH A group displayed a negative association between PTH levels and PF, based on the values obtained for the spirometric variables forced expiratory volume in 1 second (FEV1) (r = -0.54) and forced vital capacity (FVC) (r= -0.69). The average distance walked by the PTH (C) group was 343.85 ± 98.14 meters. Conclusion: The results suggest that high PTH levels have a negative effect on the PF of patients on dialysis.

Breathlessness worsened by haemodialysis

A 54 year old lady with underlying chronic lung disease on long term oxygen therapy and end stage renal disease of unknown aetiology on regular haemodialysis for two years started developing progressive shortness of breath during her routine haemodialysis. She was unable to tolerate her haemodialysis sessions which had to be terminated prematurely in view of her symptoms despite adjustment of her dry weight and treatment of anaemia. She was not in chronic fluid overload and her symptoms always worsened after initiation of haemodialysis and improved after termination of haemodialysis. She was admitted to hospital for further investigations and initially treated for a lung infection but her symptoms did not improve. A computed tomography pulmonary angiography did not reveal any evidence of pulmonary embolism, and was consistent with chronic fibrotic changes. Her hypoxemia was concluded to be due to her underlying chronic lung disease, worsened by alveolar hypoventilation during haemodialysis. Her symptoms improved slightly with supplemental oxygen during her routine haemodialysis but we had to shorten her haemodialysis duration to 3 hours.

Benefits of intradialytic physiotherapy in quality of life, pain, edema and respiratory function of patients with chronic kidney disease

Abstract Introduction: Patients with chronic kidney disease suffer from a decline in quality of life and respiratory function, for various reasons related to this condition. Objective: To verify the influence of intradialytic physiotherapy on the quality of life and respiratory function in chronic renal patients. Methods: The sample was non-probabilistic and consisted of 51 individuals, of both sexes, aged between 30 and 60 years. The WHOQOL-Bref, an evaluation form, the Manovacuometer and Peak Flow were used to detect the impact of the physiotherapeutic intervention before and after an eight-week treatment protocol. Results: There was a difference in the comparison of the general QOL before and after (p = 0.006) the intervention, as well as in the improvement of the maximal forced expiratory flow peak (p = 0.001), the PEmax (p = 0.000), peak forced expiratory flow rate (0.017) and pain (p = 0.006). There was also improvement of edema (p = 0.013) and cramps (p = 0.000). Conclusion: The benefits of intradialytic physiotherapy in improving QOL and respiratory function in chronic kidney patients are explicit.

Pulmonary Diffusion Capacity for Carbon Monoxide (DLCO) in Indonesian Patients with End-stage Renal Disease

OBJECTIVES

End-stage renal disease affects all systems in human including the respiratory system. This study aimed to discover the lung diffusion capacity of carbon monoxide (DLCO) in chronic hemodialysis patients and to establish its relation to several demographic and clinical factors as well as spirometry parameters.

MATERIAL AND METHODS

This was a cross-sectional study among chronic hemodialysis patients aged .18 years, clinically stable in the last four weeks, without prior history of lung and cardiac disorder. Spirometry and DLCO examination were performed in the span of 24 hours after hemodialysis.

OUTCOMES

There were 40 subjects analyzed. Majority of them were males (67.5%), non-smokers (55%), with a median age of 51 years, a mean body mass index of 22.6±3.9 kg/m2, a hemoglobin level of 9.5±1.3 g/dL, a median dialysis adequacy of 1.62 and a hemodialysis duration of 31.5 months. Hypertension was the most common underlying disease. About 20% of subjects had varying degrees of dyspnea. Prevalence of DLCO reduction was 52.5% with mild to moderate degree. Restrictive spirometry pattern was evident in 47.5% of subjects and obstructive pattern in 5%. There was a significant relation between DLCO reduction with smoking history (OR 4.52 [95% CI 1.04-19.6]) and also with restrictive disorder [OR 5.5 (95% CI 1.29-23.8)]. We suspected a lung parenchymal disorder as the cause of lung restriction and diffusion inhibition.

CONCLUSIONS

Reduction of lung diffusion capacity in chronic dialysis patients is common, although not accompanied by dyspnea. Risk factors for DLCO reduction are smoking history and restrictive disorder in spirometry.

Inspiratory muscle training improves respiratory muscle strength, functional capacity and quality of life in patients with chronic kidney disease: a systematic review

QUESTION

Does inspiratory muscle training improve respiratory muscle strength, functional capacity, lung function and quality of life of patients with chronic kidney disease? Does inspiratory muscle training improve these outcomes more than breathing exercises?

DESIGN

Systematic review and meta-analysis of randomised trials.

PARTICIPANTS

People with chronic kidney disease undergoing dialysis treatment.

OUTCOME MEASURES

The primary outcomes were: maximal inspiratory pressure, maximal expiratory pressure, and distance covered on the 6-minute walk test. The secondary outcomes were: forced vital capacity, forced expiratory volume in the first second (FEV₁), and quality of life.

RESULTS

The search identified four eligible studies. The sample consisted of 110 participants. The inspiratory muscle training used a Threshold^® or PowerBreathe^® device, with a load ranging from 30 to 60% of the maximal inspiratory pressure and lasting from 6 weeks to 6 months. The studies showed moderate to high risk of bias, and the quality of the evidence was rated low or very low, due to the studies' methodological limitations. The meta-analysis showed that inspiratory muscle training significantly improved maximal inspiratory pressure (MD 23 cmH₂O, 95% CI 16 to 29) and the 6-minute walk test distance (MD 80m, 95% CI 41 to 119) when compared with controls. Significant benefits in lung function and quality of life were also identified. When compared to breathing exercises, significant benefits were identified in maximal expiratory pressure (MD 6 cmH₂O, 95% CI 2 to 10) and FEV₁ (MD 0.24litres 95% CI 0.14 to 0.34), but not maximal inspiratory pressure or forced vital capacity.

CONCLUSION

In patients with chronic renal failure on dialysis, inspiratory muscle training with a fixed load significantly improves respiratory muscle strength, functional capacity, lung function and quality of life. The evidence for these benefits may be influenced by some sources of bias.

REGISTRATION

PROSPERO (CRD 42015029986). [de Medeiros AIC, Fuzari HKB, Rattesa C, Brandão DC, de Melo Marinho PÉ (2017) Inspiratory muscle training improves respiratory muscle strength, functional capacity and quality of life in patients with chronic kidney disease: a systematic review. Journal of Physiotherapy 63: 76-83].

Comparison of Gait Speed and Peripheral Nerve Function Between Chronic Kidney Disease Patients With and Without Diabetes

OBJECTIVE

To compare overall physical function, including gait speed and peripheral nerve function, between diabetic chronic kidney disease (CKD) patients and nondiabetic CKD patients and to investigate the association between gait speed and peripheral nerve function in CKD patients.

METHODS

Sixty adult CKD patients (35 with and 25 without diabetes), who received maintenance hemodialysis (HD), were included in this study. Demographic data, past medical history, current medical condition and functional data-usual gait speed, vibration perception threshold for the index finger (VPT-F) and the great toe (VPT-T), activity of daily living (ADL) difficulty, and peripheral neuropathy (PN) along with the degree of its severity-were collected and compared between the two groups. Correlations between the severity of PN and the impairment of other functions were identified.

RESULTS

Diabetic CKD patients showed significantly slower gait speed (p=0.029), impaired sensory function (VPT-F, p=0.011; VPT-T, p=0.023), and more frequent and severe PN (number of PN, p<0.001; severity of PN, p<0.001) as compared to those without diabetes. Usual gait speed had a significant negative correlation with the severity of PN (rho=-0.249, p=0.013). By contrast, VPT-F (rho=0.286, p=0.014) and VPT-T (rho=0.332, p=0.035) were positively correlated with the severity of PN. ADL difficulty was comparatively more frequent in the patients with more severe PN (p=0.031).

CONCLUSION

In CKD patients with maintenance HD, their gait speed, sensory functions, and peripheral nerve functions were all significantly impaired when they have diabetes, and the severity of PN was negatively correlated with their gait speed, sensory function, and ADL function. Adverse effects of diabetes impacted physical performance of CKD patients. The physical disability of those patients might be attributable to PN and its severity.

Excess fluid volume: sociodemographic and clinical analysis in haemodialysis patients

ABSTRACT Objective: To analyse the defining characteristics and related factors in the nursing diagnosis Excess fluid volume and its relationship to sociodemographic and clinical variables in haemodialysis patients. Method: Cross-sectional study, conducted using a form and physical examination, with a sample of 100 patients, between December 2012 and April 2013 at a university hospital and a dialysis clinic. Results: It was found 10 significant statistical associations between the defining characteristics/ related factors of Excess fluid volume and the sociodemographic and clinical variables. Conclusion: The defining characteristics and related factors of Excess fluid volume could be influenced by sociodemographic and clinical variables in haemodialysis clientele.

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.

Respiratory muscle impairment in dialysis patients: can minimal dose of exercise limit the damage? A Preliminary study in a sample of patients enrolled in the EXCITE trial

AIM

Skeletal muscle atrophy and dysfunction with associated weakness may involve the respiratory muscles of dialysis patients. We evaluated the effect of moderate-intensity exercise on lung function and respiratory muscle strength.

METHODS

Fifty-nine patients (25 F, aged 65 ± 13 years) from two centers participating in the multicenter randomized clinical trial EXerCise Introduction To Enhance Performance in Dialysis (EXCITE) were studied. Subjects were randomized into a prescribed exercise group (E), wherein subjects performed two 10-min walking sessions every second day at an intensity below the self-selected speed, or a control group (C) with usual care. Physical performance was assessed by the 6-min walk test (6MWT). Patient lung function and respiratory muscle strength were evaluated by spirometry and maximal inspiratory pressure (MIP), respectively.

RESULTS

Forty-two patients (14 F) completed the study. At baseline, the groups did not differ in any parameters. In total, 7 patients (4 in E; 3 in C) showed an obstructive pattern. The pulmonary function parameters were significantly correlated with 6MWT but not with any biochemical measurements. Group E safely performed the exercise program. At follow-up, the spirometry parameters did not change in either group. A deterioration of MIP (-7 %; p = 0.008) was observed in group C, but not in group E (+3.3 %, p = ns). In E, an increase of 6MWT was also found (+12 vs. 0 % in C; p = 0.038).

CONCLUSION

In dialysis patients, a minimal dose of structured exercise improved physical capacity and maintained a stable respiratory muscle function, in contrast to the control group where it worsened.

Impact of continuous positive airway pressure (CPAP) on the respiratory capacity of chronic kidney disease patients under hemodialysis treatment

PURPOSE

Chronic kidney disease (CKD) patients on long-term dialysis present changes in pulmonary function and respiratory muscle strength, negatively influencing physical capacity.

OBJECTIVE

To analyze the impact of a continuous positive airway pressure (CPAP) protocol on the respiratory capacity of CKD patients under hemodialysis.

METHODS

A randomized clinical trial was conducted involving 40 CKD patients 19-83 years old divided into two groups: control (n = 20) and CPAP (n = 20). Subjects were assessed on the respiratory muscle function test, maximal respiratory pressures, peak flow and 6-min walk test, at baseline and again at the 2-month follow-up. CPAP group patients were submitted to CPAP protocol (PEEP: 5 cm H2O, flow: 15 L/min, FiO2: 33 %) three times per week during hemodialysis sessions.

RESULTS

The CPAP group showed higher forced vital capacity, forced expiratory volume in one second, peak expiratory flow, maximal inspiratory pressure, peak flow, as well as lower systolic blood pressure, heart rate, respiratory rate and Borg scale, in addition to a longer distance travelled on the 6-min walk test, compared with the control group.

CONCLUSION

The introduction of a CPAP protocol during hemodialysis sessions had a positive impact on pulmonary function and physical capacity in CKD patients.