Expiratory Mouth Pressures Research Articles

Predictors of nocturnal oxygen desaturation in patients with COPD

The aim of this study was to identify factors which might predict nocturnal desaturation (defined as a fall of >4% from awake baseline level for ≥5 min) in normoxic or mildly hypoxic patients with stable COPD [arterial O 2 saturation ( SaO 2) ≥ 91%]. The study was prospective in nature, had full ethical approval and was performed in the Respiratory Department of a city teaching hospital. Thirty-three patients [mean ( sd) age 67·2 (9) years] with stable COPD [mean ( sd) FEV 1 36·8 (11·0) % pred.] were recruited via the respiratory outpatient clinics and through the respiratory wards. The following parameters were measured: daytime arterial blood gases; spirometry; lung volumes (helium dilution); single breath CO transfer factor ( T lCO and KCO); maximum inspiratory (IMP) and expiratory mouth pressures; pulse oximetry ( SpO 2) across a 6-min walk test, and SpO 2 during sleep. Seventeen patients who experienced nocturnal desaturation had significantly lower mean PaO 2 and SaO 2, and higher PaCO 2 values compared to non-desaturators. There was a positive correlation between mean nocturnal SpO 2 and daytime PaO 2, SaO 2, and minimum exercise SpO 2, and a negative correlation between mean nocturnal SpO 2 and PaCO 2, and FRC. Regression analysis revealed that daytime SaO 2 was the only independent predictor of mean nocturnal saturation (accounting for 61% of the variability in the mean nocturnal SpO 2). We observed nocturnal desaturation in all patients with a daytime SaO 2 ≤93% but in no patient with SaO 2 ≥95%. We conclude that daytime SaO 2 can be used to predict nocturnal desaturation in normoxic or mildly hypoxic patients with stable COPD. Nocturnal desaturation is likely in patients with COPD where daytime SaO 2 ≤93%, and unlikely where daytime SaO 2 ≥95%.

Expiratory muscle function in amyotrophic lateral sclerosis.

Few data exist concerning expiratory muscle function in amyotrophic lateral sclerosis (ALS). We studied 26 patients with ALS (16 with respiratory symptoms and 10 without) and measured the maximal static expiratory mouth pressure (MEP), the gastric pressure during a maximal cough (Cough Pga), and the gastric pressure after magnetic stimulation of the lower thoracic nerve roots (Tw Pga). These measurements were related to the ability to generate transient supramaximal flow during a cough (cough spikes), to arterialized capillary blood gases, and to inspiratory muscle strength. Vocal cord motion was examined endoscopically in 11 of the 16 symptomatic patients. Expiratory muscle weakness was related to inability to generate cough spikes with a threshold effect such that spikes were absent for Cough Pga < 50 cm H2O (p = 0.009) or Tw Pga < 7 cm H2O (p = 0.006) and was usually associated with inspiratory muscle weakness. However, in multivariate analysis, PaCO2 was only significantly associated with the maximal sniff esophageal pressure (p = 0.02). Symptomatic patients had significantly lower inspiratory muscle strength, whereas, of the expiratory muscle tests, only Tw Pga was significantly lower (p = 0.0009) in symptomatic patients. Abnormal vocal cord motion was observed in two of the 11 patients examined. We conclude that abdominal muscle weakness in ALS, when substantial, results in an inability to generate transient supramaximal flow during a cough. However, the primary determinant of both ventilatory failure and respiratory symptoms seems to be inspiratory muscle weakness.

Effect of lung volume reduction surgery on diaphragm strength.

Since lung volume reduction surgery (LVRS) reduces end-expiratory lung volume, we hypothesized that it may improve diaphragm strength. We evaluated 37 patients for pulmonary rehabilitation and LVRS. Before and 8 wk after pulmonary rehabilitation, 24 patients had spirometry, lung volumes, diffusion capacity, incremental symptom limited maximum exercise test, 6-min walk test, maximal static inspiratory and expiratory mouth pressures, and transdiaphragmatic pressures during maximum static inspiratory efforts and bilateral supramaximal electrophrenic twitch stimulation measured. Twenty patients (including 7 patients who crossed over after completing pulmonary rehabilitation) had baseline measurements postrehabilitation, and 3 mo post-LVRS. Patients were 58 +/- 8 yr of age, with severe COPD and hyperinflation (FEV1, 0.69 +/- 0.21 L; RV, 4.7 +/- 1.4 L). Nineteen patients had bilateral LVRS performed via median sternotomy and stapling, and 1 patient had unilateral LVRS via thorascopy with stapling. After rehabilitation, spirometry and DL(CO)/VA were not different, and lung volumes showed a slight worsening in hyperinflation. Gas exchange, 6-min walk distance, maximum oxygen uptake (VO2max), and breathing pattern during maximum exercise did not change after rehabilitation, but total exercise time was significantly longer. Inspiratory muscle strength (PImax, Pdi(max combined), Pdi(max sniff), Pdi(max), Pdi(twitch)), was unchanged after rehabilitation. In contrast, after LVRS, FVC increased 21%, FEV1 increased 34%, TLC decreased 13%, FRC decreased 23%, and FRC(trapped gas) and RV decreased by 57 and 28%, respectively. PCO2 was lower (44 +/- 6 versus 48 +/- 6 mm Hg, p < 0.003) and 6-min walk distance increased (343 +/- 79 versus 250 +/- 89 m, p < 0.001), as did total exercise time during maximum exercise (9.2 +/- 1.9 versus 6.9 +/- 2.7 min, p < 0.01). Minute ventilation (29 +/- 8 versus 21 +/- 6 L/min, p < 0.001) and tidal volume (1.0 +/- 0.33 versus 0.84 +/- 0.25 L, p < 0.001) during maximum exercise increased whereas respiratory rate was lower (28 +/- 6 versus 32 +/- 7 breaths/min, p < 0.02). Measurements of respiratory muscle strength (PImax, 74 +/- 28 versus 50 +/- 18 cm H2O, p < 0.002; Pdi(max combined), 80 +/- 25 versus 56 +/- 29 cm H2O, p < 0.01; Pdi(max sniff), 71 +/- 7 versus 46 +/- 27 cm H2O, p < 0.01; Pdi(twitch), 15 +/- 5 versus 7 +/- 5 cm H2O, p < 0.01) were all greater post-LVRS. Inspiratory muscle workload as measured by Pdi TTI was lower following LVRS (0.07 +/- 0.02 versus 0.09 +/- 0.03, p < 0.03). On multiple regression analysis, increases in PImax correlated significantly with decreases in RV and FRC(trapped gas) after LVRS (r = 0.67, p < 0.03). We conclude that LVRS significantly improves diaphragm strength that is associated with a reduction in lung volumes and an improvement in exercise performance. Future studies are needed to determine the relationship and stability of these changes over time.

M-mode Ultrasound Assessment of Diaphagmatic Excursions in Chronic Obstructive Pulmonary Disease: Relation to Pulmonary Function Test and Mouth Pressure.

Background: Respiratory muscle interaction is further profoundly affected by a number of pathologic conditions. Hyperinflation may be particularly severe in chronic obstructive pulmonary disease(COPD) patients, in whom the functional residual capacity(FRC) often exceeds predicted total lung capacity(TLC). Hyperinflation reduces the diaphragmatic effectiveness as a pressure generator and reduces diaphragmatic contribution to chest wall motion. Ultrasonography has recently been shown to be a sensitive and reproducible method of assessing diaphragmatic excursion. This study was performed to evaluate how differences of diaphragmatic excursion measured by ultrasonography associate with normal subjects and COPD patients. Methods: We measured diaphragmatic excursions with ultrasonography on 28 healthy subjects(l6 medical students, 12 age-matched control) and 17 COPD patients. Ultrasonographic measurements were performed during tidal breathing and maximal respiratory efforts approximating vital capacity breathing using Aloka KEC-620 with 3.5 MHz transducer. Measurements were taken in the supine posture. The ultrasonographic probe was positioned transversely in the midclavicular line below the right subcostal margin. After detecting the right hemidiaphragm in the B-mode the ultrasound beam was then positioned so that it was approximately parallel to the movement of middle or posterior third of right diaphragm. Recordings in the M-mode at this position were made throughout the test. Measurements of diaphragmatic excursion on M-mode tracing were calculated by the average gap in 3 times-respiration cycle. Pulmonary function test(SensorMedics 2800), maximal inspiratory(PImax) and expiratory mouth pressure(PEmax, Vitalopower KH-101, Chest) were measured in the seated posture. Results: During the tidal breathing, diaphragmatic excursions were recorded , and in medical students, age-matched control group and COPD patients, respectively. Diaphragm excursions during maximal respiratory efforts were significantly decreased in COPD patients () when compared with medical students, age-matched control group(, , p, FEVl/FVC, PEF, PIF, and height. In COPD patients, diaphragm excursions during maximal respiratory efforts were correlated with PEmax(maximal expiratory pressure), age, and %FVC. In multiple regression analysis, the combination of PEmax and age was an independent marker of diaphragm excursions during maximal respiratory efforts with COPD patients. Conclusion: COPD subjects had smaller diaphragmatic excursions during maximal respiratory efforts than control subjects. During maximal respiratory efforts in COPD patients, diaphragm excursions were well correlated with PEmax. These results suggest that diaphragm excursions during maximal respiratory efforts with COPD patients may be valuable at predicting the pulmonary function.

Effect of measurement conditions on measured levels of peak exhaled nitric oxide.

BACKGROUND: It is possible to measure nitric oxide (NO) levels in exhaled air. The absolute concentrations of exhaled NO obtained by separate workers in similar patient groups and normal subjects...

Relationship between respiratory muscle function and quality of life in sarcoidosis.

In sarcoidosis, pulmonary and general symptoms often do not correlate with radiographic stage and routinely performed lung function tests. Asymptomatic muscle involvement in sarcoidosis is common, but little is known about respiratory muscle involvement. The aim of this study was to investigate any relationships between persistent complaints and/or quality of life and respiratory muscle strength and endurance, respectively. Measurements of maximal inspiratory and expiratory mouth pressures (PI,max and PE,max), respiratory muscle endurance and routine lung function were made in 18 patients with sarcoidosis. To assess health status and quality of life, patients completed the Sickness Impact Profile (SIP). Respiratory muscle strength and endurance time were lower in the patient group than in a group of healthy controls (p=0.05). Compared to a general population, the patients with sarcoidosis were found to be limited in physical and psychosocial functioning. The respiratory muscle endurance time correlated with the SIP subscales "mobility" (r=-0.56; p<0.01), and "body care and movement" (r=-0.79; p<0.001). The total lung capacity (TLC), inspiratory vital capacity (IVC) and forced expiratory volume in one second (FEV1) were normal in all subjects. In conclusion, patients with sarcoidosis and normal lung function showed reduced respiratory muscle strength and endurance time. Correlations were found between these indices and both symptoms and certain Sickness Impact Profile domains. Therefore, we suggest inclusion of measurements of respiratory muscle strength in the assessment and follow-up of patients with sarcoidosis.

Influence of Autonomic Neuropathy of Different Severities on the Hypercapnic Drive to Breathing in Diabetic Patients

To investigate the effects of the autonomic nervous system on control of breathing, the neuromuscular (mouth occlusion pressure at 0.1 s after onset of inspiration [P0.1]) and ventilatory (minute ventilation [VE]) response to progressive hyperoxic hypercapnia was assessed in diabetic patients with autonomic dysfunction of different severity. Eighteen diabetics with autonomic neuropathy, nine with parasympathetic damage (DANp), and nine with parasympathetic and sympathetic damage (DANp+s), as indicated by marked postural hypotension, low increment of diastolic BP during sustained handgrip, and lowest resting catecholamine plasma levels, were studied together with a group of 10 diabetic patients without autonomic neuropathy (D) and a group of 10 normal subjects (C). All subjects had pulmonary function tests, including maximal voluntary ventilation and diffusion of carbon monoxide, measurements of respiratory muscle strength as maximal inspiratory mouth pressure (MIP) and maximal expiratory mouth pressure (MEP), and a CO2 rebreathing test (Read's method). Although in the normal range, lung volumes and FEV1 and forced expiratory flows were lower in the DANp and DANp+s groups than in the D and C groups, MIP and MEP were similar among C and diabetic groups, as well as resting P0.1, VE, tidal volume (VT), and respiratory rate (RR). The slope of the linear relationship between P0.1 and end-tidal PCO2 (PETCO2) was higher in DANp+s (0.63+/-0.07 cm H2O/mm Hg) than in C (0.45+/-0.06 cm H2O/mm Hg; p<0.05) and three times greater in DANp+s than in D (0.26+/-0.03 cm H2O/mm Hg; p<0.001) and DANp (0.24+/-0.03 cm H2O/mm Hg; p<0.001), who in turn showed a lower deltaP0.1/deltaPETCO2 than C. The VE increase with increasing PETCO2 was greater in DANp+s (3.70+/-0.85 L/min/mm Hg) than in DANp (2.13+/-0.20 L/min/mm Hg; p<0.05) and D (2.37+/-0.40 L/min/mm Hg; p=0.07), but not significantly higher from that of C (3.17+/-0.36 L/min/mm Hg). No differences were found for deltaVT/deltaPETCO2 among the groups, whereas the deltaRR/deltaPETCO2 relationship was steeper in DANp+s than in DANp (p<0.05) and D (p=0.055). These data reflect a depressed CO2 response both in D and DANp. The presumable decrease of the sympathetic nerve traffic in DANp+s appears to reverse this abnormality. DANp+s, however, exhibit an enhanced CO2 neuromuscular response even in respect to C, suggesting that the sympathetic nervous system might modulate the output of the respiratory centers to hypercapnic stimulus.

Cervical magnetic stimulation of the phrenic nerves in bilateral diaphragm paralysis.

Cervical magnetic stimulation (CMS) produces a greater twitch transdiaphragmatic pressure (TwPdi) than electrical stimulation. This may be because CMS produces rib cage muscle activation, thus producing an inspiratory action independent of the diaphragm. Alternatively, CMS could merely stiffen the rib cage, allowing the diaphragm to act efficiently, by contracting against a stable rib cage. To examine these two hypotheses we studied five patients with isolated bilateral diaphragm paralysis using CMS and bilateral electrical phrenic stimulation (BES). TwPdi, twitch esophageal pressure (TwPes), and twitch gastric pressure (TwPgas) were measured. We also assessed maximal sniff esophageal and transdiaphragmatic pressures (SnPes) (SnPdi), maximal inspiratory and expiratory mouth pressures (MIP) (MEP), and fall in VC on moving from an upright to a supine position. Respiratory muscle strength tests were consistent with bilateral diaphragm paralysis, and the MEPs confirmed normal expiratory muscle function. The patients were able to generate a mean SnPes of -30 cm H2O, mainly because of inspiratory activity of rib cage and neck muscles. However, TwPdi and TwPes during both CMS and BES were close to zero. We conclude that in our patients with diaphragm paralysis caused by neuralgic amyotrophy, CMS stiffens the rib cage but does not have an inspiratory action independent of the diaphragm.

TRAINING OF THE RESPIRATORY MUSCLES IN INDIVIDUALS WITH TETRAPLEGIA 233

The purpose of this study was to evaluate whether training of the innervated respiratory muscles in people with a cervical spinal cord injury will improve the strength and endurance capacity of these muscles and the exercise performance in these people. Nine individuals with tetraplegia performed an endurance training of the inspiratory muscles, twice a day for 15 min. First, the subjects trained for 6 wk with no appreciable resistance (NR), after that they trained for 6 wk with a resistance (R) of 70% of their individual maximal endurance capacity of the inspiratory muscles. The training was evaluated using the following tests: 1) a lung function test, in which the vital capacity and the forced inspiratory and expiratory volumes over 1 sec were measured; 2) a ventilation test, in which the maximal inspiratory and expiratory mouth pressure (Pimax and Pemax) and the endurance pressure (Piendu) were measured; 3) a maximal arm-cranking exercise test. Both NR and R-training had no effect on the lung function parameters, in addition, NR had no effect on ventilation nor on exercise parameters. However, after R-training Piendu increased from 35.3 ± 11.2 mmHg to 46.2± 11.8 mmHg (p=0.01), representing the endurance capacity, whereas Pimax and Pemax, representing the strength, remained unchanged. R also increased the ratio between the Pimax and the Piendu from 58.3 ± 18.6% to 77.3 ± 23.3% (p=0.02). The oxygen uptake(˙VO2 peak) at maximal exercise improved from 0.87 ± 0.49 l·min-1 to 0.98 ± 0.44 l·min-1. The results of the study indicate that training of the respiratory muscles results in an enhanced endurance capacity of these muscles and a concomittant increase in exercise performance.

Pulmonary Function in Obese Subjects With a Normal FEV1/FVC Ratio

To determine pulmonary function test (PFT) profile and respiratory muscle strength (RMS) of a group of obese individuals who did not have evidence of obstructive airway disease or other underlying diseases affecting their respiratory system. Prospective, open. PFT laboratory, VA Medical Center. Sixty-three consecutive obese (body mass index greater than 27.8 kg/m2) male subjects without overt obstructive airway disease (FEV1/FVC ratio greater than 80%). Standard PFTs and maximum static inspiratory (PImax) and expiratory (PEmax) mouth pressures were determined. RMS was calculated from the following formula: (PImax+PEmax):2. Two distinct groups were identified, those with normal maximum voluntary ventilation (MVV) (> 80% predicted) and those with low MVV. Both inspiratory and expiratory flow rates (FVC, FEV1, forced expiratory flow at 50% vital capacity [V50], maximum inspiratory flow rate [MIFR]), lung volumes (vital capacity [VC], inspiratory capacity [IC], expiratory reserve volume), PImax, and RMS were significantly lower, and residual volume/total lung capacity (RV/TLC) ratio was significantly higher in obese subjects with low MVV compared with those in whom MVV was normal. MVV correlated significantly with FVC, FEV1, V50, MIFR, TLC, VC, IC, RV/TLC, and RMS; the strongest correlation was with MIFR (r = 0.76, p < 0.0001). Standard PFTs allow recognition of a subgroup of obese subjects without overt obstructive airway disease who have more severe lung dysfunction, the marker of which is a low MVV. Peripheral airway abnormalities may be responsible for these observations.

Lung volumes and respiratory muscle strength in adult patients with childhood- or adult-onset growth hormone deficiency: effect of 12 months' growth hormone replacement therapy.

We have described impairment of the respiratory function in adult patients with childhood-onset growth hormone (GH) deficiency. The aim of the present study was to evaluate lung volumes and respiratory muscle strength in patients diagnosed as GH deficient before and after 6 and 12 months of recombinant GH treatment. Ten adults diagnosed as GH deficient in childhood, ten adults diagnosed as GH deficient in adulthood and ten healthy subjects entered the study. For each subject, evaluation of respiratory function followed the same standard approach, consisting of respiratory muscle strength assessment, record of flow-volume curves, measurement of static lung volumes and lung diffusing capacity. Childhood-onset GH-deficient patients had a significant reduction of maximal inspiratory (p < 0.01) and maximal expiratory (p < 0.05) mouth pressures. Total lung capacity, vital capacity and functional residual capacity were significantly reduced compared to healthy subjects (p < 0.05). Conversely, residual volume and diffusing lung capacity did not show any significant change. No significant change of the ratio between the percentage forced expiratory volume in 1 s and the forced vital capacity was observed. The decrease of respiratory mouth pressures was not correlated to the decrease of lung volumes. Adult-onset GH-deficient patients had only a significant reduction of maximal expiratory pressure compared to healthy subjects (p < 0.05). After 6 months of treatment no significant differences in any of the evaluated parameters were found. After 12 months of treatment patients with childhood-onset GH deficiency show a significant improvement of lung volumes (p < 0.01) and maximal respiratory mouth pressures (p < 0.005), whereas adult-onset GH-deficient patients show a significant improvement of maximal expiratory pressure (p < 0.05). In conclusion, the results of this study showed that adult patients affected with childhood-onset GH deficiency suffer from an impairment of the ventilatory function due to a reduction of lung volumes and a decrease of respiratory pressures probably due to a reduction of respiratory muscle strength. This impairment was reversed after 12 months of treatment with recombinant GH. Conversely, adult-onset GH-deficient patients had only an impairment of the maximal expiratory pressure, probably due to respiratory muscle weakness re-established after 12 months of GH therapy.

Energy cost of exercise in multiple sclerosis patients with low degree of disability.

In 10 patients (five females) suffering from multiple sclerosis with mild degree of disability, (EDSS ranging from 0 to 2) and in 10 age and sex matched control subjects we investigated lung function, respiratory muscles strength and cardiorespiratory response to incremental exercise in order to assess the metabolic cost of exercise. In the absence of any impairment of lung volumes and flows and in- and expiratory maximal mouth pressures, at peak of exercise oxygen consumption (VO2max = 1886 +/- 145 ml/min) and workload (Wmax = 137 +/- 9.8 watts) were slightly diminished in patients, as compared with controls (VO2max = 2246 +/- 196 ml/min and Wmax = 164 +/- 14.7 watts). These findings were associated with an increased heart rate (HR) and reduced oxygen pulse (VO2/HR) at the same workloads. During the whole exercise, however, the slope of the linear relationship between VO2 and work exhibited by the patients, amounting to 9.9 +/- 0.6 ml/min/watt, was similar to that of the controls (10.9 +/- 0.42 ml/min/watt). Incidentally, both at rest and during exercise, the patients showed a significantly greater minute ventilation (VE) due to a faster respiratory rate, associated with an augmented dead space (P < 0.05). We conclude that an increase of metabolic cost of exercise does not occur in multiple sclerosis patients with mild disability, suggesting a lack or a low degree of spasticity and/or ataxia elicited by the effort. Thus, their exertional capacity appears to be limited mainly by a poor training. The tachypnea observed in these patients at rest and during exercise was unexpected and the reason for adopting such a pattern of breathing is unclear.

Obstructive and restrictive pulmonary dysfunctions in Parkinson's disease

Pulmonary dysfunction was investigated in fifty-eight Parkinson's patients. Clinical disability was assessed by the Unified Parkinson's Disease Rating Scale. Pulmonary dysfunction was studied by spirometry with flow-volume loops, body plethysmography with lung volumes computation and maximal inspiratory and expiratory static mouth pressures. Forced vital capacity (FVC), forced expiratory volume in 1 min (FEV1), FEV1 FVC% and arterial PO2 and PCO2 were significantly below normal values. Residual volume (RV) and total rows were above normal values. Thirty-six had upper airway obstruction as judged by inspiratory flow peaks (PIF) <31/s and FEV1 PEF% (expiratory flow peak) > 8.51/min and MEF50 MIF50 > 1. Eighteen patients had a central (FEV1 < 80% and FEV1 FVC% < 80% of normal values) or peripheral (maximal expiratory flow between 75% and 25% of FVC and maximal expiratory flow after expiration of 50% below 70% of normal values) obstructive pattern. Sixteen patients had a restrictive dysfunction as judged by a total lung capacity < 85% or FVC < 80% with FEV1 FVC% > 80%. Sixteen patients had air trapping (RV > 120% and RV TLC > 40%) and seven patients had lung insufflation (TLC > 120%). Rigidity, Rx signs of cervical arthrosis and limitations for passive movement of neck were higher in patients with central or peripheral airway obstruction. Bradykinesia and Rx signs of dorsal arthrosis was higher in patients with upper airway obstruction. Restrictive dysfunction was not related to tremor, rigidity or bradykinesia. The present data support the hypothesis that Parkinson patients present a high risk for pneumologic disturbances. These pulmonary dysfunctions are induced by the simultaneous action of a group of factors including the degree of bradykinesia or rigidity and the musculoskeletal limitations of vertebral column probably induced by chronic anomalous posture.

Nutritional status and mortality in chronic obstructive pulmonary disease.

The role of nutritional status in the prognosis of subjects with severe chronic obstructive pulmonary disease was studied in a cohort of Canadian men and women followed for 3 to 5 yr. A total of 348 subjects who were recruited for a study of negative pressure ventilation were evaluated for lung function and body weight, and a subset who entered hospital for the study (n=184) had baseline measures of diffusing capacity, maximal inspiratory and expiratory mouth pressure (PImax and PEmax), and blood gases. Predictors of survival were analyzed using Cox regression models. In the total cohort, low body mass index (BMI) and use of home oxygen were independently associated with reduced survival. In the hospitalized group, predictors of respiratory mortality were elevated PaCO2 and low BMI, PImax, and diffusing capacity. PaO2 (measured on oxygen therapy), FEV1, PEmax, age, smoking behavior, and gender were not associated with survival. The predictors of total mortality were similar, except that BMI was no longer significant. In conclusion, low body weight, a potentially modifiable factor, was associated with respiratory mortality, but whether it has a casual effect or is a marker of declining health can only be resolved through an intervention trial.

Respiratory muscle strength after lung resection with special reference to age and procedures of thoracotomy.

Changes in respiratory muscle strength after lung resection were examined concerning age and procedures of thoracotomy. Maximum inspiratory (MIP) and expiratory (MEP) mouth pressure were measured before operation and 1, 2, 4, and 12 weeks after operation in 81 patients undergoing lung resection. In 48 patients undergoing pneumonectomy, lobectomy, or segmentectomy, patients older than 70 showed a significantly lower MIP and MEP before operation and throughout the postoperative period compared to younger ones (P < 0.01). Furthermore, the older patients showed a significantly lower percentage of postoperative MIP and MEP 4 weeks after operation than the younger ones (P < 0.01). In 31 patients undergoing lung wedge resection, patients undergoing limited thoracotomy (LT) and video-assisted thoracic surgery (VATS) showed significantly higher percentages of postoperative MIP and MEP than those undergoing posterolateral thoracotomy (PLT) 1 and 2 weeks after operation (P < 0.01 or 0.05). But there was no significant difference in the values between LT and VATS. We concluded that (1) elderly patients suffered respiratory muscle weakness before and after operation and their postoperative recovery of respiratory muscle strength was slower than in younger patients, and (2) VATS and LT resulted in more rapid recovery of respiratory muscle strength than PLT, but the difference between VATS and LT was not significant.

Obstructive and restrictive pulmonary dysfunction increases disability in Parkinson disease

Objective:: The purpose of this study was to determine in Parkinson disease the impact of pulmonary dysfunction on daily living activities (DLA). Patients:: Extrapyramidal motor impairment, pulmonary dysfunction, and DLA disabilities were studied in 58 Parkinson patients consecutively enrolled in a rehabilitation service at a universal hospital. Main Outcome Measures: Extrapyramidal motor impairments were assessed by the United Parkinson's Disease Rating Scale (IPDRS) and the DLA disabilities by the ipdrs, Hoehn-Yahr, and Schwab-England scales. The pulmonary dysfunctions were assessed by spirometry with flow-volume loops, body plethysmography with lung volumes computation, and maximal inspiratory and expiratory slatic mouth pressures. Results: Parkinson patients showed important modifications of pulmonary function with a decrease in forced vital capacity, forced expiratory volume in the first minute, and arterial P o 2, and an increase in residual volume and total airway resistance (RAW). In addition, they showed a high incidence of airway ventilatory obstructions and restrictive dysfunction. The impact of lung disease on daily living activities in Parkinson disease patients was higher in subjects with restrictive pulmonary dysfunctions (Schwab-England test and turning in bed and adjusting bedclothes, walking, falling, and freezing when walking items of UPDRS) and airway obstructions (handling utensils, dressing and hygiene items of UPDRS). Concusions: Airway obstructions or restrictive pulmonary dysfunctions present a high prevalence in Parkinson disease, contributing as a main factor for DLA dysfunctions. The evauation and rehabilitation of respiratory disturbances should be systematically included in the management of these patients.

Respiratory Rehabilitation, Exercise Capacity and Quality of Life in Chronic Airways Disease in Old Age

Respiratory rehabilitation improves exercise capacity and quality of life in younger patients but is untried in the aged. We aimed to: (a) assess repeatability of the 6-minute walk test, factors affecting it and its relation to quality of life in elderly patients with chronic obstructive airways disease (COAD); (b) assess compliance of such patients with an intensive respiratory rehabilitation protocol; (c) pilot the assessment of the effect of respiratory rehabilitation on the 6-minute walk test in these patients. Seventeen subjects with stable, symptomatic COAD were recruited, 15 (six men), 70-89 (mean 76) years, completed the study. Mean (standard deviation) 1-second forced expiratory volume (FEV1) = 49 (5)% predicted. Six-minute walk tests were repeated single-blind, 2-10 days apart. Quality of life was measured using Guyatt respiratory questionnaire. Patients underwent 12 weeks incremental respiratory rehabilitation (x4/day step-ups, unweighed arm raises, inflating balloons). Baseline 6-minute walk was repeatable and was correlated with the log Guyatt dyspnoea score (r = 0.65, p = 0.006). In multiple regression neither age nor FEV1 predicted walk distance: body mass index, maximal expiratory mouth pressure; calorie intake. Mean (SEM) 6-minute walk distance after-rehabilitation was greater than baseline (p = 0.003). Elderly patients with COAD tolerate intensive respiratory rehabilitation and a controlled, blinded study is needed.

Impairment of lung volumes and respiratory muscle strength in adult patients with growth hormone deficiency

Little is known of the respiratory function in patients with growth hormone (GH) deficiency. The aim of the present study was to evaluate lung volumes and respiratory muscle strength in patients diagnosed as GH deficient in childhood. Ten patients diagnosed as GH deficient in childhood and ten healthy subjects entered the study. For each subject the evaluation of respiratory function followed the same standard approach, consisting of respiratory muscle strength assessment, recording of flow-volume curves, measurement of static lung volumes and lung diffusing capacity. Both maximal inspiratory and expiratory mouth pressures were decreased in GH deficiency. Vital capacity, N2 functional residual capacity and total lung capacity were significantly reduced when compared to healthy subjects. Conversely, the residual volume and diffusing lung capacity to CO did not show any significant change. No significant change of percentage forced expiratory volume in 1 s/forced vital capacity ratio was observed. The decrease of respiratory mouth pressures was not correlated to the decrease of lung volumes. In conclusion, the results of this study show that adult patients affected with childhood onset GH deficiency suffer from impairment of ventilatory function and a decrease of respiratory muscle pressures, probably due to reduction of respiratory muscle strength.

Effects of posture on respiratory mechanics in obesity

Increased abdominal mass in obesity should enhance normal gravitational effects on supine respiratory mechanics. We have examined respiratory impedance (forced oscillation over 4-26 Hz applied at the mouth during tidal breathing), maximum inspiratory and expiratory mouth pressures (MIP and MEP), and maximum effort flow-volume curves seated and supine in seven obese subjects (O) (mean age 51 yr, body mass index 43.6 kg/m2) and seven control subjects (C) (mean age 50 yr, body mass index 21.8 kg/m2). Seated mean total lung capacity was smaller in O than in C (82 vs. 100% of predicted); ratio of functional residual capacity (FRC) to total lung capacity averaged 43% in O and 61% in C (P < 0.01). Total respiratory resistance (Rrs) at 6 Hz seated was higher in O (4.6 cmH2O.l-1.s) than in C (2.2 cmH2O.l-1.s; P < 0.001); total respiratory reactance (Xrs) at 6 Hz was lower in O than in C. In C, on changing to the supine posture, mean Rrs at 6 Hz rose to 2.9 cmH2O.l-1.s, FRC fell by 0.68 liter, and Xrs at 6 Hz showed a small fall. In O, despite no further fall in FRC, supine Rrs at 6 Hz increased to 7.3 cmH2O.l-1.s, and marked frequency dependency of Rrs and falls in Xrs developed. Seated, MIP and MEP in C and O were similar; supine there were small falls in MEP and maximum expiratory flow in O. The site and mechanism of the increase in supine Rrs and reduction in supine Xrs and the mechanism maintaining supine FRC in obesity all need further investigation.

Dynamic respiratory functions and expiratory mouth pressures in obese and non-obese patients during subarachnoid (SAB) anaesthesia for caesarean section

Dynamic respiratory functions and expiratory mouth pressures in obese and non-obese patients during subarachnoid (SAB) anaesthesia for caesarean section