Biomedical subjects

T Wanke

Publications and source records attributed to T Wanke.

At least 19 recordsLinked to original sources

PubMed2000

Dose-dependent effects of inspiratory muscle training in neuromuscular disorders.

The goal of this study was to show whether a correlation exists between the intensity of specific respiratory muscle training and the improvement of strength and endurance in inspiratory musculature in patients with neuromuscular disorders (NMD). Sixteen patients with NMD (13 with Duchenne muscular dystrophy and 3 with spinal muscular atrophy) performed inspiratory muscle training (IMT) at home with a special training apparatus for 9 months. Maximal inspiratory mouth pressure (PI(MAX)) and 12s-maximum voluntary ventilation (12s-MVV) test served as parameters for inspiratory muscle strength and endurance, respectively. In patients whose inspiratory vital capacity (VC(in)) declined by less than 10% during the year before training began (n = 10), a significant positive correlation was found between the number of successfully completed strength and endurance exercises and the improvement of PI(MAX) (P < 0.05) and 12s-MVV (P < 0.05). In patients whose VC(in)-decline exceeded 10% (n = 6), indicating more progressive respiratory system involvement of the disease, no significant correlation between the improvement of PI(MAX) and 12s-MVV and the intensity of training was found. In patients with NMD, the effects of IMT-runs are dose-dependent, provided that the respiratory system involvement of the disease is only slowly progressive.

Adolescent↗

PubMed2000

Is long-term functional outcome after lung volume reduction surgery predictable?

OBJECTIVE: The aim of this retrospective study was to analyze which preoperative parameters might predict a persistent improvement in forced expiratory volume in 1 s (FeV1) 1 year after surgery. METHODS: Seventy consecutive lung volume reduction surgery (LVRS) patients (age, 56.5+/-1.2 years) with a follow-up period of at least 1 year were analyzed (from September 1994 to September 1997). The patients were described by lung function tests, blood gas analysis, ventilatory mechanics (intrinsic positive endexpiratory pressure (PEEP)) and morphometric data (degree of heterogeneity, DHG; degree of hyperinflation, DHI; severity of parenchymal destruction, SPD) preoperatively. Based on the postoperative course of FeV1 (percentual increase compared with preoperative values, % increase), patients were divided into four groups: group A, (n=21) no improvement (FeV1</=20% increase); group B, (n=10) FeV1>/=20% increase, which declined to preoperative values after 1 year; group C, (n=18) FeV1, 20-40% increase, sustaining at 1 year; group D, (n=21) FeV1>/=40% increase, sustaining at 1 year. The statistics comprised of analysis of variance (ANOVA) and chi-square testing, with values presented as means+/-SEM. RESULTS: No differences were found for lung function parameters (FeV1: 27.7+/-2.7, 26.0+/-2.5, 23. 9+/-2.2 and 23.9+/-1.9% predicted, in groups A, B, C and D, respectively). Arterial blood gas levels preoperatively revealed significant differences between the groups; the arterial pO(2) was 66.2+/-1.2 mmHg in groups A+B compared with 61.8+/-1.5 mmHg in groups C+D (P=0.030). The arterial pCO(2) was 39.2+/-1.1 mmHg in groups A+B compared with 43.3+/-1.5 mmHg in groups C+D (P=0.038). The morphometric data had a strong trend towards higher heterogeneity in groups C and D. Marked DHI was found in 59 and 81% of patients in groups A+B versus C+D, respectively (P=0.121). Marked DHG was present in 22 and 54% of patients in groups A+B versus C+D, respectively (P=0.010). CONCLUSION: Preoperative arterial pO(2) and pCO(2), and the DHG are predictors for long-term benefit after LVRS with regard to the FeV1, 1 year postoperatively.

Analysis of Variance↗

PubMed2000

Feedback-controlled negative pressure ventilation in patients with stable severe hypercapnic chronic obstructive pulmonary disease.

BACKGROUND: In recent studies, the efficacy of intermittent rest of the inspiratory muscles as an option of treating patients with severe chronic obstructive pulmonary disease (COPD) has become questionable. OBJECTIVE: The aim of our study was to analyze the effects of feedback-controlled intermittent negative pressure ventilation (INPV) on stable, but severely hypercapnic COPD patients. METHODS: 21 clinically stable, hypercapnic patients with severe COPD underwent INPV with chest shells for 3 weeks, 6 h a day. The INPV sessions were optimized by a visual biofeedback system, which enabled control over the decrease in diaphragmatic activity. Respiratory muscle (RM) function parameters, lung function parameters, blood gases and exercise capacity were analyzed. RESULTS: In the end, 19 patients concluded INPV treatment. They had PaO(2) of 56.5 +/- 11.8 mm Hg, PaCO(2) of 50.2+/-2.7 mm Hg (mean +/- SD) and FEV(1) of 27.8 +/- 4.3% predicted before treatment. There was no statistically significant change in lung function parameters, RM function parameters, physical performance and level of dyspnea after 3 weeks of INPV. CONCLUSION: We conclude that intermittent RM rest induced by INPV can relax inspiratory muscles in most patients with stable severe COPD, but fails to improve RM function and exercise capacity.

Aged↗

PubMed1999

Neural drive to the diaphragm after lung volume reduction surgery.

STUDY OBJECTIVES: The aim of this study was to investigate prospectively the changes in neural drive to the diaphragm in the first year after lung volume reduction surgery (LVRS) in patients with COPD. PATIENTS AND METHODS: In 14 patients with severe emphysema (mean +/- SD; age, 53.7 +/- 8.3 years; FEV(1), 0.64 +/- 0. 18 L; residual volume [RV], 5.33 +/- 1.25 L; PaO(2), 62.3 +/- 9.0 mm Hg; PaCO(2), 39.0 +/- 6.0 mm Hg), we assessed lung function, arterial blood gases, maximal exercise capacity (Wmax), and oxygen uptake (f1.gif" BORDER="0">O(2)max); intrinsic positive end-expiratory pressure (PEEPi); diaphragmatic strength (transdiaphragmatic pressure, Pdisniff) and endurance capacity (tlim); central diaphragmatic drive assessed by root mean square analysis of the esophageal electromyogram (rmsdia); and isotime dyspnea during loaded breathing tests (BS). RESULTS: Despite a significant increase (expressed as a percentage of baseline) in FEV(1) (40.6%) and a decrease in RV (30.0%) and PEEPi (75.7%) 1 month after LVRS, the improvements in Wmax (31.2%) and f1.gif" BORDER="0">O(2)max (13.7%); Pdisniff (25.4%) and tlim (64.9%); rmsdia (34.6%); and BS (21.7%) did not reach statistical significance (p < 0.05) until 6 months after LVRS. Arterial blood gases did not change significantly. Significant correlations were found between decrease in rmsdia and changes in PEEPi (r = 0.69), Wmax (r = -0.56), Pdisniff (r = -0.65), tlim (r = -0.59), and BS (r = 0.71) 6 months after LVRS. CONCLUSIONS: Our results show that LVRS is able to increase the efficacy of the respiratory pump and by this way reduce ventilatory drive and respiratory effort sensation.

Diaphragm↗

PubMed1998

Morphologic grading of the emphysematous lung and its relation to improvement after lung volume reduction surgery.

BACKGROUND: The morphologic criteria for lung volume reduction surgery, such as severity and heterogeneity of disease, differ widely between patients, and this makes any comparison of functional results between centers difficult. Here we present a morphologic scoring system and describe its possible relation to functional results after lung volume reduction operations. METHODS: Between September 1994 and December 1996, 47 consecutive patients underwent bilateral lung volume reduction operations. The morphology of emphysema was quantified with standard chest roentgenograms and computed tomographic imaging, which were used to define the following four variables: degree of hyperinflation (grade 0 to 4), degree of impairment in diaphragmatic mechanics, degree of heterogeneity (grade 0 to 4), and severity of parenchymal destruction (range, 0 to 48). RESULTS: All four variables showed good reproducibility. Degree of heterogeneity had a significant influence on functional improvement in terms of forced expiratory volume in 1 second (p = 0.0413, r2 = 0.11). Severity of parenchymal destruction was significantly associated with 30-day mortality: patients who died after operation (n = 4) had a severity of parenchymal destruction of 28.4 +/- 2.1 compared with 21.3 +/- 1.0 for those who survived (n = 43) (p = 0.003). CONCLUSIONS: This morphologic scoring system is easy to use, is reproducible, and allows quantification of the morphology of emphysema, thereby allowing definition of different patient subgroups. Such an exact morphologic quantification may help in the comparison of functional results between centers. Furthermore, the risk factors for certain morphologic subgroups, such as patients with a homogeneous distribution pattern, may be clarified in the future.

Adult↗

PubMed1998

Chronic hypercapnia should not exclude patients from lung volume reduction surgery.

OBJECTIVE: Chronic hypercapnia is still considered to increase the risk for perioperative mortality and therefore to be a contraindication for lung volume reduction surgery (LVRS). The aim of this study was to analyse the influences of hypercapnia upon postoperative outcome. METHODS: The functional improvement (preop vs. 3 months postop) and clinical outcome was studied in 22 patients with chronic hypercapnia (preoperative arterial pCO2 > or = 45 mmHg) who underwent LVRS between 9/94 and 2/97 and were compared to all other patients (n = 58) without hypercapnia. Data are expressed as the mean +/- SEM. RESULTS: The 30-day mortality was 9.1% (2/22) in patients with chronic hypercapnia (HC) and 5.2% (3/58) in patients with normal arterial pCO2 levels (control) (P = n.s). The stay on the ICU (3.5 +/- 0.8 vs. 2.1 +/- 0.3 days) and duration of chest drainage (7.3 +/- 1.2 vs. 7.2 +/- 0.8 days) was similar between both groups (HC vs. control) (P = n.s). The preoperative lung function (% of predicted) and blood gas (mmHg) parameters were significantly worse in HC patients compared to control patients. In both groups significant functional improvements were observed: FeV1 in the control group increased by 37% within the first 3 months (29.1 +/- 1.7% of predicted vs. 39.9 +/- 3.1% of predicted, P = 0.0198). In the HC group, FeV1 increased by 73% which was even higher than in the controls (19.5 +/- 1.5% of predicted vs. 33.7 +/- 4.7% of predicted, P = 0.0385). All patients of both groups who died perioperatively had a significantly higher severity of parenchymal destruction than those who survived (P = 0.0277 and 0.0380, respectively). CONCLUSIONS: Patients with chronic hypercapnia alone, had no significantly higher mortality and morbidity, and therefore should not be excluded from LVRS. However, the presence of additional risk factors, such as homogeneity of disease, high degree of parenchymal destruction or pulmonary hypertension should be considered as contraindications for the procedure.

Case-Control Studies↗

PubMed1998

Ventilatory mechanics and gas exchange during exercise before and after lung volume reduction surgery.

Many patients with emphysema are able to meet ventilatory demands during resting conditions, but they show severe limitations during exercise. To examine the effect of lung volume reduction (LVR) surgery on exercise performance and the mechanism of possible improvement, we measured ventilatory mechanics (pulmonary resistance [RL], work of breathing [WOB], dynamic intrinsic positive end-expiratory pressure [PEEPi,dyn], peak expiratory flow rate [PEFR]), breathing pattern, oxygen uptake (V O2), and carbon dioxide removal (V CO2) at rest and during cycle ergometry in eight patients before and 3 mo after LVR surgery. Ventilatory mechanics were evaluated assessing esophageal pressure and air flow. Three months after LVR surgery, the tolerated workload was doubled when compared with the preoperative value (p < 0.0005), associated with a reduction of RL (p < 0.05), PEEPi,dyn (p < 0.005), and WOB (p < 0. 005) at comparable workloads. Maximal ventilatory capacity and maximal tidal volume (VT) increased significantly (p < 0.01). Maximal V O2 increased from 474 +/- 23 to 601 +/- 16 ml/min (p < 0. 005) and maximal V CO2 from 401 +/- 13 to 558 +/- 21 ml/min (p < 0. 005), though no significant difference at comparable workloads could be observed. In conclusion, emphysema surgery leads to an improvement of ventilatory mechanics at rest and during exercise. Higher maximal VT and minute ventilation were observed, resulting in improvement of maximal V O2 and V CO2 and exercise capacity.

Aged↗

PubMed1997

Functional improvement after volume reduction: sternotomy versus videoendoscopic approach.

BACKGROUND: Volume reduction has been proved to increase ventilatory mechanics in diffuse, nonbullous lung emphysema. However, the best approach is still controversial. METHODS: We retrospectively compared the perioperative data of and functional results in 15 patients having sternotomy (group I) with those of 15 patients having a videoendoscopic approach (group II). RESULTS: The 30-day mortality was 2 patients in group I and 1 patient in group II. Mean duration of chest tube drainage was 8.7 +/- 1.8 days and 8.0 +/- 1.9 days and mean hospital stay, 12.3 +/- 1.9 and 12.5 +/- 2.1 days in groups I and II, respectively. Work of breathing decreased from 1.89 +/- 0.33 J/L and 1.76 +/- 0.22 J/L preoperatively to 0.75 +/- 0.06 J/L and 0.8 +/- 0.06 J/L (p < 0.01 and p < 0.05, respectively) after 3 months; and intrinsic positive end-expiratory pressure decreased from 7.15 +/- 1.31 cm H2O and 6.24 +/- 1.33 cm H2O to preoperatively 0.79 +/- 0.46 cm H2O and 1.13 +/- 0.44 cm H2O (p < 0.005 and p < 0.01, respectively) after 3 months in groups I and II, respectively. Forced expiratory volume in 1 second increased from preoperative values of 21.6% +/- 2.9% and 25.3% +/- 2.4% of predicted to 34.5% +/- 5.0% and 40.9% +/- 7.5% of predicted after 3 months (p < 0.05 in both groups) in groups I and II, respectively. CONCLUSIONS: Both surgical approaches resulted in similar substantial improvement in lung function and physical fitness. The incidence of air leakage, the duration of chest tube drainage, and the hospital stay were the same for both procedures.

Case-Control Studies↗

PubMed1997

Functional improvements in ventilatory mechanics after lung volume reduction surgery for homogeneous emphysema.

OBJECTIVE: Between September 1994 and August 1996 Lung Volume Reduction Surgery (LVRS) was performed through median sternotomy, videoendoscopically or by thoracotomy in 54 consecutive patients (age 34-69 years, mean 48 years). METHODS: The areas with the most destroyed lung parenchyma were resected by means of linear stapling devices. A total of 5 patients died postoperatively due to aspiration pneumonia, multiorgan failure and acute hepatic failure respectively. A marked functional improvement and increase in quality of life was observed in the remaining patients. RESULTS: Residual volume decreased from 317.0 +/- 12.4% of predicted (%p) preoperatively to 226.2 +/- 8.8%p within the first month (P = 0.0001). FeV1 significantly increased from 23.7 +/- 1.3%p preoperatively to 36.3 +/- 4.1%p during the first 6 months postoperatively (P = 0.0016). Radiological signs of hyperinflation and distention of the thorax preoperatively improved to a more dome shaped diaphragm and narrowed intercostal spaces. These morphologic changes resulted in better ventilatory muscle function. The intrinsic PEEP significantly decreased from 5.92 +/- 0.64 cm H2O preoperatively to 1.70 +/- 0.25 cm H2O postoperatively (P = 0.0001). The work of breathing decreased from 1.58 +/- 0.09 J/l preoperatively to 0.99 +/- 0.07 J/l postoperatively (P = 0.0001). CONCLUSIONS: In conclusion, LVRS is an excellent therapeutic option for patients with homogeneous emphysema with additional signs of severe hyperinflation.

Female↗

PubMed1997

Changes in ventilatory mechanics and diaphragmatic function after lung volume reduction surgery in patients with COPD.

BACKGROUND: Lung volume reduction (LVR) has recently been used to treat severe emphysema. About 25% of the volume of each lung is removed with this method. Little is known about the mechanism of functional improvement so a study was undertaken to investigate the changes in ventilatory mechanics and diaphragmatic function in eight patients after LVR. METHODS: Measurements of work of breathing (WOB), intrinsic positive end expiratory pressure (PEEPi), dynamic compliance (Cdyn), and arterial carbon dioxide tension (PaCO2) were performed on the day before surgery and daily for seven days after surgery, as well as one, three, and six months after surgery. All measurements were performed on spontaneously breathing patients, simultaneously assessing oesophageal pressure via an oesophageal balloon catheter and air flow via a tightly adjusted mask. Diaphragmatic function was evaluated by measuring oesophageal and transdiaphragmatic pressure (Pdi) preoperatively and at one, three, and six months postoperatively. RESULTS: Mean forced expiratory volume in one second (FEV1) was 23 (3.6)% predicted, and all patients were oxygen dependent before the-operation. One day after LVR the mean decrease in WOB was 0.93 (95% confidence interval (CI) 0.46 to 1.40) joule/l, the mean decrease in PEEPi was 0.61 (95% CI 0.35 to 0.87) kPa, and the mean increase in Cdyn was 182.5 (95% CI 80.0 to 284.2) ml/kPa. Similar changes were found seven days and six months after surgery. PaCO2 was higher on the day after the operation but was significantly reduced six months later. Pdi was increased three and six months after surgery. CONCLUSIONS: Ventilatory mechanics improved immediately after LVR, probably by decompression of lung tissue and relief of thoracic distension. An improvement in diaphragmatic function three and six months postoperatively also contributes to improved respiratory function after LVR.

Aged↗

PubMed1997

The effect of lung transplantation on the neural drive to the diaphragm in patients with severe COPD.

Little is known about the effects of lung transplantation (LT) on the neural drive to the diaphragm and on the endurance of respiratory muscles in patients with severe chronic obstructive pulmonary disease (COPD). The aim of this study was to evaluate these effects of single-lung (SLT) and double-lung transplantation (DLT). The neural drive to the diaphragm was assessed during fatiguing inspiratory threshold loading manoeuvres in six SLT recipients, six DLT recipients and seven patients with severe COPD, by using diaphragmatic surface electromyograms. During threshold loading, the patients had to generate 80% of their maximal transdiaphragmatic pressure with each breath. The endurance of inspiratory muscles was defined as the time from the beginning of a resistive breathing trial until exhaustion (t lim). In DLT recipients and even in SLT recipients (on both sides), neural activation of the diaphragm was significantly lower than in COPD patients (p < 0.05). However, no statistically significant difference in t lim was seen between LT recipients and COPD patients. The data suggest that single-lung and double-lung transplantations cause a significant decrease of the neural drive to the diaphragm, while the endurance of inspiratory muscles is well-preserved in patients with advanced chronic obstructive pulmonary disease. This may contribute to reduced sensation of inspiratory effort during ventilatory stress, thus improving the quality of life.

Diaphragm↗

PubMed1996

Defective endogenous opioid response to exercise in type I diabetic patients.

Plasma beta-endorphin (beta-E) concentration was determined before, during, and after a standardized incremental exercise test to maximal capacity in eight type I diabetic patients and eight normal control subjects. Diabetic patients were studied under normoglycemic and hyperglycemic conditions in a single-blind random fashion to differentiate between the effects of acute hyperglycemia and of diabetes per se on the beta-E response to exercise. The perceived magnitude of leg effort elicited by exercise was evaluated using a category scale. Whereas plasma beta-E concentrations increased in control subjects with increasing workload, causing significantly higher beta-E levels at the end of exercise than at the beginning (P < .001), no such increase could be observed in the diabetic patients under normoglycemic and hyperglycemic conditions. In addition, baseline plasma beta-E concentrations were significantly lower in normoglycemic (P < .01) and hyperglycemic (P < .001) diabetic patients than in control subjects. Even during the recovery period, patients' beta-E levels remained significantly lower than those of control subjects. At submaximal levels of power output, the perceived intensity of leg effort was significantly higher in normoglycemic and hyperglycemic diabetic patients than in control subjects. We conclude that in type I diabetic patients, the ability of the endogenous opioid system to respond to exercise-induced stress is impaired under hyperglycemic and even under normoglycemic conditions. Considering the effect of endogenous opioids on stress tolerance, such changes may compromise exercise performance in diabetic patients.

Adult↗

PubMed1996

[Innovative respiratory muscle training for patients with Duchenne muscular dystrophy--a psychological evaluation].

For neuromuscular patients with progressive respiratory muscle weakness a new training apparatus was developed, which allows a home training of strength as well as endurance of the inspiratory muscles, especially the diaphragma. A significant positive training result could be proved in a comparative study between 2 groups of 15 Duchenne muscular dystrophy (DMD) patients each (8). By the end of the training the satisfaction of patients with the new training equipment was evaluated by means of a questionnaire. The degree of satisfaction was determined at a 10-point scale. Critical ideas were used for improvement of the newly developed training apparatus.

Adult↗

PubMed1996

[Changes in ventilatory mechanics in emphysema].

The increased airway resistance and hyperinflation characteristic of chronic obstructive pulmonary disease (COPD) affect respiratory muscle function, particularly that of the diaphragm. The compensatory changes of the breathing pattern due to expiratory flow limitation lead to a further increase of the mechanical load on the ventilatory muscles during forced ventilation. Therapeutic strategies which reduce hyperinflation and the increased airway obstruction, improve the neuromechanical efficiency of the inspiratory muscles.

Airway Resistance↗

PubMed1996

[Lung volume reduction in emphysema--experience and results of the first 2 years].

Between September 1994 and August 1996 Lung Volume Reduction Surgery (LVRS) was performed through median sternotomy, videoendoscopically or by thoracotomy in 60 patients (age 33 to 80 years, mean 56.7 years). All these patients had severe emphysema despite maximal conservative and physical therapy. The areas with the most destroyed lung parenchyma were resected by means of linear stapling devices, 3 patients (20%) out of 15 who were operated via sternotomy died postoperatively due to aspiration pneumonia, multiorgan failure and acute hepatic failure. In the videoendoscopic group with 45 patients, 2 patients (4.4%) died due to multiorgan failure and cardiorespiratory failure. 72.7% of the remaining patients showed a significant functional improvement (postoperative FEV1 > 130% of the preoperative value) with a marked decrease of dyspnea. There was no significant improvement in 23.7% of the patients (postoperative FEV1 = 90 to 110% of the preoperative value) and 3.6% of the patients had a functional deterioration. Residual volume decreased from 317.0 +/- 12.4% of predicted (%p) preoperatively to 226.2 +/- 8.8 %p within the first month (p = 0.0001). FEV1 significantly increased from 23.7 +/- 1.3 %p preoperatively to 36.6 +/- 4.1 %p during the first 6 months postoperatively (p = 0.0016). Radiological signs of hyperinflation and distention of the thorax preoperatively improved to narrowed intercostal spaces and a more shaped diaphragm. These morphological changes resulted in better ventilatory muscle function. The intrinsic PEEP significantly decreased from 5.92 +/- 0.64 cm H2O preoperatively to 1.70 +/- 0.25 cm H2O postoperatively (p = 0.0001). The work of breathing decreased from 1.58 +/- 0.09 J/l preoperatively to 0.99 +/- 0.07 J/l postoperatively (p = 0.0001). In conclusion, LVRS is an excellent therapeutic option for patients with severe emphysema and additional signs of severe hyperinflation with significant postoperative functional improvement and marked increase in quality of life.

Female↗

PubMed1996

[Surgical technique and results of bilateral volume reduction in patients with pulmonary emphysema].

Between 9/94 and 3/96 volume reduction was performed on 29 patients by a median sternotomy or videoendoscopic approach. Perioperative mortality occurred in three patients. The residual volume decreased within the first month from preoperative 308.8 +/- 13.4% of predicted (%p) to 217.9 +/- 12.7%p (p < 0.05). FeV1 significantly improved to 37.9 +/- 4.6%p after 3 months, versus 23.5 +/- 1.8%p preoperatively (p < 0.05). Intrinsic PEEP substantially decreased from 6.69 +/- 0.91 cm H2O preop to 0.93 +/- 0.28 cm H2O initially after surgery (p < 0.005). This was paralleled by the work of breathing: 1.78 +/- 0.2 J/l preoperatively versus 0.77 +/- 0.04 J/l postoperatively (p < 0.005). In conclusion, VR is a safe and successful option for patients with pulmonary emphysema, who show signs of marked hyperinflation.

Female↗

PubMed1995

Phrenic neuropathy in chronic renal failure.

BACKGROUND: Peripheral neuropathy and alterations in diaphragmatic muscle function are frequently caused by uraemia. Phrenic nerve function in patients with end stage renal failure, however, has not been examined to date. METHODS: An electrophysiological study of the phrenic nerve was performed to determine its possible involvement in 32 nondiabetic patients with end stage renal disease undergoing chronic haemodialysis. RESULTS: Seventeen patients had electrophysiological signs of peripheral neuropathy in at least one of the investigated nerves and 14 of the 17 showed pathological phrenic nerve latencies. Delayed phrenic nerve latencies correlated clearly with pathological peroneal nerve conduction velocities. CONCLUSIONS: Phrenic neuropathy is a frequent complication of uraemia.

Adolescent↗

PubMed1995

Effect of autonomic neuropathy on ventilatory response to progressive hypercapnia in dialysis patients.

The impact of autonomic neuropathy (common in patients on haemodialysis) on ventilatory response to hypercapnia has been studied. We investigated cardiac reflex tests in 20 patients on chronic haemodialysis (8 patients were found with and 12 without neuropathy of the autonomic nervous system). Using the hyperoxic CO2-rebreathing method (according to Read), we tested the above-mentioned two groups of patients and compared them with 14 healthy control subjects. Accumulation of CO2 in blood with hyperoxic CO2 rebreathing stimulates central chemoreceptors, and therefore causes a progressive rise in minute ventilation. In patients with autonomic neuropathy (n = 8), ventilatory response to increasing pCO2 was significantly lower than that in the controls (1.7 +/- 0.3 versus 3.2 +/- 0.5 l/min/mmHg, P < 0.001). On the other hand ventilatory response in patients without autonomic damage (n = 12) showed no significant difference when compared to controls (3.1 +/- 0.8 l/min/mmHg). There were no differences in lung function, arterial blood gas analysis, blood chemistry, duration on dialysis, and demographic data when comparing the patients with and those without autonomic damage. Our analysis shows different patterns of ventilatory response to increasing pCO2 in patients on haemodialysis. Autonomic neuropathy has to be considered when rebreathing tests are interpreted. The clinical relevance of these findings needs further investigation.

Analysis of Variance↗