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PubMed1995

[Clinical effects of inspiratory muscle training in patients with chronic airflow limitation].

The clinical role of inspiratory muscle training (IMT) in chronic obstructive pulmonary disease (COPD) has not been established, because data on its clinical effect is scarce and controversial. To further investigate these aspects we studied 20 COPD patients (FEV1 37 +/- 3% P) who were randomly and double blindly trained for 30 minutes a day during 10 weeks using a threshold inspiratory trainer with either 30% (group 1) or 10% (group 2) of PIMax as a training load. The training load was crossed after each patient completed 10 weeks of training. Effects were assessed through changes in PIMax, dyspnea through the transition dyspnea index (ITD) and the respiratory effort with Borg's score. Walking capacity was measured with the six minutes walking distance test (6WD) and depression symptoms with Beck's score. Daily life activities were also assessed. Results showed that after 10 weeks of IMT, PIMax increased in both groups (p < 0.05), dyspnea improved in group 1 as compared to group 2 (p < 0.04), 6WD increased significantly in patients of group 1, who also complained of less dyspnea (p < 0.05). Depression scores fell significantly in group 2. Daily activities improved more in group 1. After the crossover patients in group 1 disclosed a significant deterioration in PIMax whereas group 2 disclosed significant improvements in PIMax, dyspnea and 6WD. We conclude that IMT using a threshold device with 30% PIMax is a useful procedure for the treatment of severe COPD patients.

Activities of Daily Living↗
PubMed1997

Determinants of the tension-time index of inspiratory muscles in children with cystic fibrosis.

Nutritional status and chronic pulmonary hyperinflation can alter respiratory muscle function in cystic fibrosis (CF). This study investigated: 1) whether inspiratory muscle function is reduced in children with stable CF in comparison with healthy controls; and 2) the mechanisms leading to inspiratory muscle weakness, which probably predispose to respiratory muscle fatigue. We determined the tension-time index of the inspiratory muscles (TTMUS) noninvasively at rest in 16 children with mild to moderate CF (mean age, 11 +/- 2 years) and 10 healthy controls (mean age, 11 +/- 2 years). The TTMUS was determined as follows: TTMUS = TI/TTOT.PI/PIMAX, where PI is the mean inspiratory pressure estimated from the measure of mouth occlusion pressure (P0.1), PIMAX is the maximal inspiratory pressure, and TI/TOT is the duty cycle. The results showed similar nutritional status in both groups, as well as mild to moderate airway obstruction, hyperinflation, and trapped gas in the CF group. In this group only, a significant inverse relationship was found between TI/TOT and PI/PIMAX[TITTOT = 0.482 - (0.388PI/PIMAX), r = -0.53; p < 0.05]. These patients also had greater TTMUS (TTMUS = 0.087 +/- 0.030 in CF vs. 0.056 +/- 0.014 in controls, P < 0.01) that increased with decreasing lean body mass (r = -0.70, P < 0.005), with increasing percent predicted functional residual capacity (r = 0.70, P < 0.05), and increasing volumes of trapped gas (r = 0.77, P < 0.01). The multiple linear regression analysis for these factors was significant (R2 = 0.84, P < 0.01); however, the partial regression coefficient was significant only for lean body mass (r2 = 0.60, P < 0.05). Therefore, muscle mass appeared as the strongest determinant of TTMUS in CF. This study used a noninvasive method to assess the inspiratory muscle performance in children with CF. The results suggest impairment in inspiratory muscle function in these children despite good nutritional status and only mild to moderate alteration in pulmonary function tests. In addition, we were able to investigate some of the determinants of inspiratory muscle weakness, namely, muscle mass, hyperinflation, and trapped gas, and found that muscle mass played a predominant role.

Body Mass Index↗
PubMed2000

Maximal inspiratory flow rates in patients with COPD.

OBJECTIVES: To assess the relevance of maximal inspiratory flow rates (MIFR) in the assessment of airway obstruction in COPD. SETTING: University teaching hospital. PARTICIPANTS: Ten consecutive COPD patients (O group; mean [+/- SD] age, 58.5+/-8.3 years) and 10 matched healthy subjects (H group; mean age, 58.7+/-7.4 years). MEASUREMENTS: Lung volumes, FEV(1), specific airway conductance, single-breath lung diffusing capacity, MIFR, and maximal expiratory flow rates (MEFR). RESULTS: Mean FEV(1)/vital capacity (VC) was 74.7% in the H group and 37.8% in the O group (p<0.001). Total lung capacity was higher (p<0.001) in the O group compared with the H group. Lung diffusing capacity was less than half in the O group compared with the H group (p<0.001). MEFR at all lung volumes were lower in the O group (p<0.001). MIFR were comparable in the two groups, except at 25% inspired VC, where MIFR were lower in the O group (p< 0.05). CONCLUSION: MIFR are less sensitive than MEFR to detect airway obstruction in COPD patients. Yet, the interest of MIFR lay in the possibility to separate intrinsic from extrinsic involvement of airways. A normal MIFR associated with low MEFR, as in the present study, suggests either a lack of parenchymal support, an increased collapsibility of the airways, or a reversible peripheral airway narrowing. A fixed, generalized airway narrowing would be associated with a decrease of both MIFR and MEFR.

Forced Expiratory Flow Rates↗
PubMed1982

Respiratory muscle strength and maximal voluntary ventilation in undernourished patients.

To assess the effect of chronic debilitation on respiratory muscle function, we studied 16 poorly nourished (PN) patients without pulmonary disease, and 16 well-nourished (WN) subjects matched for age and sex. Body weight, vital capacity (VC), maximal voluntary ventilation (MVV), and maximal static inspiratory and expiratory pressures (PImax and PEmax) were measured and expressed as percent predicted. Respiratory muscle strength (RMS) was calculated as (% PImax + % PEmax)2. Body weight was 71% predicted in the PN group and 104% in the WN group. The RMS, MVV, and VC were 37%, 41%, and 63%, respectively, of the values in the WN group (p less than 0.001). The 60% reduction in RMS was shared almost equally among inspiratory and expiratory muscles, and PEmax was linearly related to body weight. Because malnutrition reduces both respiratory muscle strength and MVV, it may well impair respiratory muscle capacity to handle increased ventilatory loads in thoracopulmonary disease.

Adolescent↗
PubMed1985

Inspiratory muscle dysfunction and unexplained dyspnea in systemic lupus erythematosus.

The role of inspiratory muscle dysfunction in lung volume restriction and unexplained dyspnea was studied in 16 consecutive patients with systemic lupus erythematosus. Maximal mouth inspiratory pressure (PIM) and maximal transdiaphragmatic pressure (Pdi max) were measured. Pdi and its components were determined during quiet breathing. No significant association was found between the activity of the disease, several serologic markers, and the inspiratory muscle dysfunction. No specific anti-skeletal muscle antibody was found in these patients. Significant correlations were found between the degree of dyspnea and PIM (r = -0.69, P less than 0.01) and Pdi max (r = -0.75, P less than 0.001); however, dyspnea did not correlate with specific lung compliance. Vital capacity correlated significantly with the degree of dyspnea (r = -0.813, P less than 0.001) and with Pdi max (r = 0.544, P less than 0.05). No correlation was found between vital capacity and specific lung compliance. We conclude that inspiratory muscle dysfunction can be an important mechanism in the pathogenesis of the lung volume restriction and dyspnea in patients with systemic lupus erythematosus.

Adolescent↗
PubMed2001

Spirometric performance in Belgian Blue calves: II. Analysis of environmental factors and estimation of genetic parameters.

Genetic parameters and environmental effects for spirometric variables (SV) in calves were estimated using 734 Belgian Blue calves (15 to 297 d of age), sired by 20 AI bulls. For each calf, the following SV were measured: 1) the average ventilation (l/min) recorded during the 15 s of maximal ventilatory changes induced by lobeline administration (0.25 mg/kg, i.v.) (15-s MV(L)); 2) the vital capacity, and the maximal peak expiratory and inspiratory flows recorded after lobeline administration; and 3) the ventilatory reserve (15-s MV(L) - ventilation at rest). Analysis of environmental factors showed age of calf, herd, sex, and vaccination status had significant effects on SV. A sire model and a multiple-trait derivative-free REML procedure were used to estimate genetic parameters for SV, body weight, and muscling score. Heritabilities for SV ranged from 0.28 +/- 0.11 to 0.44 +/- 0.16. Genetic correlations among SV varied from 0.76 to 0.98 and environmental correlations from 0.69 to 0.80. Genetic correlations of SV with body weight (0.25 to 0.56) and with muscling score (0.21 to 0.76) were positive, as were environmental correlations of SV with body weight (0.44 to 0.70) and muscling score (0.09 to 0.25). These results suggest that selection may improve SV without impairing other traits of economic importance.

Animals↗
PubMed1990

Breathing pattern affects respiratory heat loss but not bronchoconstrictor response in asthma.

To determine whether changes in breathing pattern alone affect respiratory heat loss (RHL) and the constrictor response to cold dry gas hyperpnea in asthmatic subjects, we performed the following 2 part study: first we measured RHL in 8 asthmatic and 8 normal subjects during controlled eucapnic hyperpnea while they breathed at inspiratory to expiratory ratios (I/E) of 1:3, 3:1, and 2:2, and we recorded postchallenge forced expiratory volume in 1 sec (FEV1) in the asthmatic group; we then performed the same measurements in 8 asthmatic and 8 normal subjects at fixed target minute ventilation (VE) for tidal volumes of 0.2 X Forced vital capacity (FVC), 0.4 X FVC, and 0.6 X FVC by varying the target respiratory rate appropriately. Our results show that (1) increasing I/E ratio or tidal volume-frequency ratio (VT/f) at fixed VE produced small but statistically significant increases (p less than 0.05) in overall heat loss per unit volume of respired gas (RHL/VE) in both asthmatic and nonasthmatic subjects of 1-4 cal/L; (2) changes in breathing pattern alone did not affect bronchoconstrictor response as assessed by lack of change in slopes and intercepts of % delta FEV1 vs. RHL dose-response curves; and (3) the increase in RHL per unit volume of respired gas resulting from increasing VT/f ratios during cold gas hyperpnea was significantly greater in asthmatic than in nonasthmatic subjects. We conclude that changes in breathing pattern may affect overall RHL measured at the mouth, although the maximum effect of such changes in both asthmatic and nonasthmatic subjects is small (10-15%); that such changes do not significantly alter airway constrictor response in asthmatic persons; and (3) that the effects of changing breathing pattern on RHL may be more pronounced in asthmatic than nonasthmatic subjects, which suggests that the asthmatic group may be less able to adapt to factors that alter the magnitude and site of RHL.

Adult↗
PubMed1989

Relationship between respiratory muscle function and age, sex, and other factors.

To investigate the effects of gender and age on respiratory muscle function, 160 healthy volunteers (80 males, 80 females) were divided into four age groups. Twenty-eight of the male subjects were smokers. After the subjects were familiarized with the experimental procedure, respiratory muscle strength, inspiratory muscle endurance, and spirometric function, including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC, tidal volume, breathing rate, and duty cycle, were measured. The respiratory muscle strength was indicated by the maximal static inspiratory and expiratory pressures (PImmax and PEmmax). Inspiratory muscle endurance was determined by the time the subject was able to sustain breathing against an inspiratory pressure load on a modified Nickerson-Keens device. The results showed that 1) except for inspiratory muscle endurance and FEV1/FVC, men had greater respiratory muscle and pulmonary functions than women, 2) respiratory muscle function and pulmonary function decreased with age, 3) smoking tended to lower duty cycle and FEV1/FVC and to enhance PE,mmax, and 4) inspiratory muscle endurance was greater in men who were physically active than in those who were sedentary. Therefore we conclude that there are sexual and age differences in respiratory muscle strength and pulmonary function and that smoking or physical activity may affect respiratory muscle function.

Adult↗
PubMed1999

Peak inspiratory flow through Turbuhaler in chronic obstructive airways disease.

Many patients with chronic obstructive airways disease (COAD) receive therapy by the inhaled route. This study was performed to assess whether patients with severe COAD could generate sufficient peak inspiratory flow (PIF) through Turbuhaler (Astra, Sodertalje) to operate it effectively. One hundred patients (45 men, 55 women, mean age 69.1 years) with COAD (mean (SD) duration 17.7 (16.3) years) and peak expiratory flow (PEF) < or = 200 l min-1 or forced expiratory volume in 1 sec (FEV1) < or = 1 litre were studied. A series of randomly assigned inspiratory and expiratory lung function tests were contiguously performed, using portable spirometers, within 48 h of a screening visit. An empty Turbuhaler was used in the study. The patients' normal medication was not restricted. Sixty-six patients were previous smokers, eight occasional smokers, 19 habitual smokers and seven had never smoked. Mean (SD) FEV1 was 0.7 (0.2) 1 and mean PEF was 182 (68) l min-1. All patients were able to generate PIF through Turbuhaler (PIF-T) of 28 l min-1 (mean 53; range 28-78 l min-1). Eighty-three patients generated PIF-T of > or = 40 l min-1. PIF-T correlated with PIF without Turbuhaler (r = 0.35), PEF (r = 0.3), FEV1 (r = 0.2) and forced vital capacity (FVC) (r = 0.23) although the relationships were too weak to be used to predict PIF-T. The results suggest that patients with severely limited lung function caused by COAD can operate Turbuhaler effectively.

Adolescent↗
PubMed2005

Estimation of functional residual capacity at the bedside using standard monitoring equipment: a modified nitrogen washout/washin technique requiring a small change of the inspired oxygen fraction.

We developed a modified nitrogen washin/washout technique based on standard monitors using inspiratory and end-tidal gas concentration values for functional residual capacity (FRC) measurements in patients with acute respiratory failure (ARF). For validation we used an oxygen-consuming lung model ventilated with an inspiratory oxygen fraction (Fio(2)) between 0.3 and 1.0. The respiratory quotient of the lung model was varied between 0.7 and 1.0. Measurements were performed changing Fio(2) with fractions of 0.1, 0.2, and 0.3. In 28 patients with ARF, duplicate measurements were performed. In the lung model, an Fio(2) change of 0.1 resulted in a value of 103 +/- 5% of the reference FRC value of the lung model, and the precision was equally good up to an Fio(2) of 1.0 with a value of 103 +/- 7%. In the patients, duplicate measurements showed a bias of -5 mL with a 95% confidence interval [-38; 29 mL ]. A comparison of a change in Fio(2) of 0.1 with 0.3 showed a bias of -9 mL and limits of agreement of [-365; 347 mL]. This study shows good precision of FRC measurements with standard monitors using a change in Fio(2) of only 0.1. Measurements can be performed with equal precision up to an Fio(2) of 1.0.

Adult↗
PubMed2000

Diffusion-convection equation solved in parallel regions of the lung.

The single path model of airway gas transport was incorporated into each of Cruz (Cruz, J. C. Respir. Physiol. 86:1-14, 1991). Thus, the effect of time on the predicted gas fractions in and out of the lung could be evaluated. Two experimental maneuvers were simulated: (1) fast inhalation of an argon-oxygen mixture from a functional residual capacity and fast exhalation to residual volume, including inspiratory breath holdings of 5-20 s, and (2) the standard single-breath nitrogen washout test. Expired argon and nitrogen are predicted within a +3% error of the experimental data with no breath holding. Breath holding predictions were at variance with experimental results because the solution of the diffusion-convection equation produced even mixing in the alveoli at the end of inspiration. The minimum square of the difference between the experimental data (standard single-breath nitrogen washout test) and those provided by the model was 0.0016. This model is capable of generating a nitrogen expirogram with four phases when a vital capacity of oxygen is inhaled. However, the model failed to produce a sharp distinction between phase 3 and phase 4. Thus, we conclude that uneven emptying of parallel regions generates any expirogram (a fast or slow expiratory maneuver). The alveolar gas stratification that is created during inspiration disappears at the end of the inspiratory maneuver. As a result, breath holding maneuvers cannot be predicted in the anatomical model used.

Biomedical Engineering↗
PubMed2006

The cortico-diaphragmatic pathway involvement in amyotrophic lateral sclerosis: neurophysiological, respiratory and clinical considerations.

Cortico-diaphragmatic pathway was investigated by means of transcranial magnetic stimulation (TMS), in 14 patients affected by definite amyotrophic lateral sclerosis (ALS) without clinical signs of respiratory impairment. Spirometry, gas analysis, and measurement of static inspiratory and expiratory pressures were performed in all patients. Forced vital capacity, forced expiratory volume at the first and second peak expiratory flow, sniff effort from FRC level (SNIP), maximal inspiratory and expiratory pressure at mouth (MIP/MEP), maximal transdiaphragmatic pressure (Pdimx) were considered. TMS was performed, recording by surface electrodes from hemidiaphragm, bilaterally. Latency of cortical and spinal motor-evoked potentials (Cx-MEP/Sp-MEP) and central motor conduction time (CMCT) were measured. None of the patients showed altered spirometry and gas levels. Seven patients showed decreased Pdimx and eight of MEP values. Four patients showed a delayed Sp-MEP. In one patient the Cx-MEP was abolished while the mean values of both Cx-MEP and CMCT were significantly increased (19.2+/-4.1 ms, P<0.0001; 10.8+/-4.8 ms, P<0.0001). Cx-MEP and CMCT did not show significant correlations with any of the respiratory measures. The patients with prolonged Sp-MEP, showed longer disease duration, lower Norris score, lower Pdimx and MEP values. In conclusion, cortico-diaphragmatic study is a sensitive measure to reveal subclinical diaphragmatic impairment although not correlated to respiratory measures.

Adult↗
PubMed1998

Chronic obstructive pulmonary disease: strategies to improve functional status.

People with chronic obstructive pulmonary disease (COPD) experience deterioration in functional status, therefore improving functional status is a major goal of treatment. We reviewed interventions to improve functional status in people with COPD published from 1980 through September 1996. Randomized controlled clinical trials were reviewed to document outcomes in terms of functional capacity and functional performance for the following interventions: pharmacologic therapy including theophylline, inhaled bronchodilators, steroids, antianxiolytics and antidepressants; general exercise strategies including exercise training, exercise and comprehensive pulmonary rehabilitation, and upper extremity training; inspiratory muscle therapy including inspiratory muscle training and inspiratory muscle rest; nutritional therapy; oxygen therapy; and specialized nursing care. Improvements for functional capacity were documented in terms of strength of the inspiratory muscles and upper extremities, walking tests, and peak oxygen uptake. Most interventions were targeted to enhance functional capacity, and few were aimed at enhancing functional performance. Further research is needed to examine the relationship between functional capacity and functional performance and to design and test interventions to improve functional performance.

Humans↗
PubMed1989

Effects of water temperature on pulmonary volumes in immersed human subjects.

Pulmonary volumes and capacities have been measured at three water temperatures (Tw = 25, 34, 40 degrees C) in standing subjects immersed up to the shoulders. The comparison of data obtained in air with those obtained in thermoneutral immersion (Tw = 34 degrees C) confirms the results previously published in several studies. The comparison of data obtained in immersion at different Tw shows: 1. A significant decrease in vital capacity (VC) with bath temperature (VC 40 degrees C greater than VC 34 degrees C greater than VC 25 degrees C). The same decrease is observed in the inspiratory reserve volume (IRV) while the expiratory reserve volume (ERV), the residual volume (RV) and the functional residual capacity (FRC) do not vary. 2. A significant decrease in maximum breathing capacity (MBC) with bath temperature (MBC 40 degrees C greater than MBC 25 degrees C). 3. A significant increase in tidal volume (VT) in cold or hot water compared to thermoneutral water (VT40 degrees C greater than VT34 degrees C; VT34 degrees C less than VT25 degrees C) during quiet breathing. Breathing frequency does not change, thus ventilation (V) follows the same evolution as VT. The relative abdominal (ABD) contribution to VT, estimated by a double belt inductance plethysmograph, is reduced at Tw = 25 degrees C but unchanged at Tw = 40 degrees C compared to thermoneutral bath. Beside variations in the metabolic state, the variations of the pulmonary volumes as a function of Tw are estimated to be mainly due to alterations in respiratory muscles functioning.

Adult↗
PubMed1985

Respiratory load compensation in chronic airway obstruction.

To assess respiratory neuromuscular function and load compensating ability in patients with chronic airway obstruction (CAO), we studied eight stable patients with irreversible airway obstruction during hyperoxic CO2 rebreathing with and without a 17 cmH2O X l-1 X s flow-resistive inspiratory load (IRL). Minute ventilation (VE), transdiaphragmatic pressure (Pdi), and diaphragmatic electromyogram (EMGdi) were monitored. Pdi and EMGdi were obtained via a single gastroesophageal catheter with EMGdi being quantitated as the average rate of rise of inspiratory (moving average) activity. Based on the effects of IRL on the Pdi response to CO2 [delta Pdi/delta arterial CO2 tension (PaCO2)] and the change in Pdi for a given change in EMGdi (delta Pdi/delta EMGdi) during rebreathing, two groups could be clearly identified. Four patients (group A) were able to increase delta Pdi/delta PaCO2 and delta Pdi/delta EMGdi, whereas in the other four (group B) the IRL responses decreased. All group B patients were hyperinflated having significantly greater functional residual capacity (FRC) and residual volume than group A. In addition the IRL induced percent change in delta Pdi/delta PaCO2, and delta VE/delta PaCO2 was negatively correlated with lung volume so that in the hyperinflated group B the higher the FRC the greater was the decrease in Pdi response due to IRL. In both groups the greater the FRC the greater was the decrease in the ventilatory response to loading. Patients with CAO, even with severe airways obstruction, can effect load compensation by increasing diaphragmatic force output, but the presence of increased lung volume with the associated shortened diaphragm prevents such load compensation.

Diaphragm↗
PubMed1990

Asbestos-related pulmonary disease in boilermakers.

Boilermakers are skilled building tradesmen who construct, repair, and dismantle boilers. The present study reports on the evaluation of members of a Michigan boilermaker's union for the presence of signs and symptoms of chronic pulmonary disease. Study variables included standardized evaluations of chest x-ray findings, pulmonary function testing, physical examination, and respiratory symptoms. An overall participation rate of 69% was achieved. A non-participant survey identified no significant differences between participants and non-participants in dyspnea, cough, age, or smoking history. Among participants with greater than 20 years experience in the trade, the mean FVC was 91% of predicted; the FEV1 was 86% of predicted; 25% showed at least a 1/0 profusion of interstitial markings on chest x-ray; 30% had bilateral pleural abnormalities; and 52% had audible inspiratory rales on physical examination. Forced vital capacity and forced expiratory volume at one second both decreased with years in the trade. Chest x-ray findings of interstitial fibrosis and pleural plaques were related to ten or more years in the trade, as were respiratory symptoms of pulmonary rales, wheeze, and dyspnea.

Age Factors↗
PubMed1995

Effects of exercise during normoxia and hypoxia on the growth hormone-insulin-like growth factor I axis.

The response of plasma insulin-like growth factor I (IGF I) to exercise-induced increase of total human growth hormone concentration [hGHtot] and of its molecular species [hGH20kD] was investigated up to 48 h after an 1-h ergometer exercise at 60% of maximal capacity during normoxia (N) and hypoxia (H) (inspiratory partial pressure of oxygen = 92 mmHg (12.7 kPa); n = 8). Lactate and glucose concentrations were differently affected during both conditions showing higher levels under H. Despite similar maximal concentrations, the increase of human growth hormone (hGH) was faster during exercise during H than during N[hGHtot after 30 min: 8.6 (SD 11.4) ng.ml-1 (N); 16.2 (SD 11.6) ng.ml-1 (H); P < 0.05]. The variations in plasma [hGH20kD] were closely correlated to those of [hGHtot], but its absolute concentration did not exceed 3% of the [hGHtot]. Plasma IGF I concentration was significantly decreased 24 h after both experimental conditions [N from 319 (SD 71) ng.ml-1 to 228 (SD 72) ng.ml-1, P < 0.05; H from 253 (SD 47) to 200 (SD 47) ng.ml-1, P < 0.01], and was still lower than basal levels 48 h after exercise during H [204 (SD 44) ng.ml-1, P < 0.01]. Linear regression analysis yielded no significant correlation between increase in plasma [hGHtot] or [hGH20kD] during exercise and the plasma IGF I concentration after exercise. It was concluded that the exercise-associated elevated plasma [hGH] did not increase the hepatic IGF I production. From our study it would seem that the high energy demand during and after the long-lasting intensive exercise may have overridden an existing hGH stimulus on plasma IGH I, which was most obvious during hypoxia.

Adult↗
PubMed2005

Subclinical electrophysiological alterations of phrenic nerve in chronic inflammatory demyelinating polyneuropathy.

Alterations of the phrenic nerve (PN) and pulmonary function tests (PFTs) have been described in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). This study was aimed at assessing the relationship between PN and respiratory function in CIDP patients without clinical signs of respiratory failure. Bilateral PN and right median nerve conduction studies were carried out along with blood gas analysis and PFTs: maximal inspiratory pressure; maximal expiratory pressure; forced vital capacity. The amplitude of the compound muscle action potential of the PN was seen to be altered in 19/24 (79%) patients and latency in 22 (92%). Eighteen patients (75%) showed at least one abnormal PFTs or CO2 partial pressure value. Electrophysiological alterations of the PN were observed in a high percentage of the CIDP patients studied. No statistically significant correlation was observed between PN and PFTs alterations.

Adult↗