[Interpreting carbon monoxide transfer coefficient: significance and difficulties]. / Intérêts et difficultés d'interprétation du coefficient de transfert du CO (TLCO/VA).

INTRODUCTION: Interpreting measurements of carbon monoxide can be problematic. STATE OF THE ART: The transfer factor (TLCO) is usually calculated by multiplying the decrease in alveolar CO concentration between the beginning and the end of a 10 second breath hold (KCO) by the alveolar volume (VA). Thus a reduced TLCO may occur due to either a low KCO, a reduced VA, or a combination of both. PERSPECTIVES: A careful examination of KCO and VA will usually suggest a specific explanation for a reduction in TLCO. In restrictive lung diseases from extrapulmonary origin, TLCO is low but TLCO/VA [[/INF 120% of the reference values. In interstitial lung disease, the value of TLCO/VA depends on whether the loss of lung units is diffuse or not, and probably also on the status of the microcirculation. In airflow obstruction, a low VA is caused by uneven distribution of inspired He/CO mixture within the breath-hold time. CONCLUSIONS: The transfer factor for carbon monoxide is best interpreted in terms of its components, alveolar volume and carbon monoxide transfer coefficient.

Clinical experience with functional electrical stimulation-assisted gait with Parastep in spinal cord-injured patients.

STUDY DESIGN: Clinical evaluation of the Parastep method, a six-channel transcutaneous functional electrical stimulation device, in spinal cord-injured patients. OBJECTIVES: To investigate the motor performances of this new technique regarding energy expenditure and to evaluate its advantages and limitations, especially in social activities involving ambulation. METHODS: This study was conducted in 15 thoracic spine-injured patients. The lesion was complete except in two patients. The gait ability and the functional use were judged clinically. Energy cost was evaluated from heart rate, peak oxygen uptake, and lactatemia. RESULTS: Thirteen patients completed the training (mean: 20 sessions) and achieved independent ambulation with a walker. The mean walking distance, without rest, was 52.8 +/- 69 m, and the mean speed was 0.15 +/- 0.14 m/sec. One patient with incomplete lesion, who had been nonambulatory for 8 months after the injury, became able to walk without functional electrical stimulation after five sessions. The follow-up was 40 +/- 11 months. Five patients pursued using functional electrical stimulation-assisted gait as a means of physical exercise but not for ambulation in social activities. The patients experienced marked psychological benefits, with positive changes in their way of life. In three subjects, a comparison of physiologic responses to exercise between a progressive arm ergometer test and a walking test with the Parastep (Sigmedics, Inc., Northfield, IL) at a speed of 0.1 m/sec was performed, showing that the heart rate, the peak oxygen uptake, and lactatemia during gait were close to those obtained at the end of the maximal test on the ergometer. CONCLUSIONS: In spite of its ease of operation and good cosmetic acceptance, the Parastep approach has very limited applications for mobility in daily life, because of its modest performance associated with high metabolic cost and cardiovascular strain. However, it can be proposed as a resource to keep physical and psychological fitness in patients with spinal cord injury.

Blood lactate concentrations during exercise: effect of sampling site and exercise mode.

BACKGROUND: The purpose of the study was to compare blood lactate concentrations determined in blood sampled from three sites (finger capillary, ear-lobe capillary, and forearm vein) during exercise on three different ergometers (a cycle ergometer, a treadmill and an arm-crank ergometer). METHODS: A total of 312 well-trained subjects performed either a six-minute steady-state exercise (n = 219) or an incremental exercise test until exhaustion (n = 93). Blood was sampled from two sites after each exercise test and at the end of each stage of the incremental protocol, 852 pairs of blood samples were analysed. RESULTS: Results showed that, when exercise was performed on a cycle ergometer or a treadmill, no significant differences between venous and ear capillary samples were observed whereas finger capillary values were higher. On an arm-crank ergometer, venous and finger capillary lactate concentrations were usually higher than ear capillary values with some discrepancies depending on the times of sampling. CONCLUSIONS: We conclude that lactate values may differ depending on the sampling site and the type of exercise mode. An ear capillary sample may be preferred because it is less affected by lactate release in the arms and easier to obtain.

[Diffusing capacity for carbon monoxide (T(LCO)) and oxygen saturation during exercise in patients with cystic fibrosis]. / Capacité de transfert du monoxyde de carbone (TLCO) et saturation artérielle à l'exercice chez les patients atteints de mucoviscidose.

OBJECTIVES: To estimate the value of diffusing capacity for carbon monoxide (T(LCO)) in patients with cystic fibrosis and to evaluate its ability to predict arterial desaturation during exercise. METHOD: Fourty-four patients (9-30 years) with cystic fibrosis performed pulmonary function tests with measure of T(LCO) and a bicycle incremental exercise test. They represent a wide variation in disease severity: mean Shwachman score: 77.8 (range: 40-100), mean FEV1%: 72.8 (range: 17-131). This study investigated the relationship between T(LCO), lung volumes and exercise data. RESULTS: T(LCO) remained normal for a long time in patients with cystic fibrosis: 82% of them show a normal T(LCO) (mean value: 91.3% of predicted). T(LCO) was significantly correlated with FEV(1), residual volume, maximal work load and maximum oxygen uptake. A fall in arterial oxygen saturation was uncommon in our study (five patients) and not significantly correlated with T(LCO). CONCLUSIONS: T(LCO) is a good criter of severity of cystic fibrosis but remains unreliable to predict values above which physical activity is safe, without arterial desaturation. Exercise tests should be proposed in order to evaluate exercise adaptation of each patient and determine which factor limits maximal performance.

[Asthma and scuba diving Absolute contraindication? in all asthma patients?]. / Asthme et pratique de la plongée sous-marine.

Physical and psychological fitness are required for scuba diving, leading to medical contraindications in certain subjects. Asthma, a condition exhibiting increasing prevalence in the general population is currently considered an absolute contraindication for scuba diving by the French Federation for Submarine Sports and Education (FFESSM). There is however no documented evidence demonstrating a higher risk in asthmatic divers. Our English-speaking colleagues have suggested that certain asthmatic subjects could participate in scuba diving sports under certain conditions without any higher risk compared with non-asthmatic divers. We recall here the impact of diving on respiratory function and potential consequences in asthmatic subjects, proposing that the formal contraindication against scuba diving should be maintained for asthmatic patients who experience frequent symptoms (step 2 or more of the International Consensus Report on Diagnosis and Treatment of Asthma) and/or have a baseline obstructive syndrome. It would appear reasonable to discuss the contraindication concerning patients with rare acute episodes and who have a perfectly normal respiratory function. The question of bronchodilator inhalation prior to diving may be a question to debate. However, such a proposal cannot be considered to be valid unless well-conducted studies of the clinical manifestations are available (frequency and severity of the acute episodes, triggering factors) for the diver candidate. Because of the highly restrictive nature of the contraindication notification and the absence of arguments backing up the decision, the question should be put to competent authorities (sports federations, learned societies) in order to ascertain the pathophysiological mechanisms involved and collect reliable epidemiological data before proposing a consensus discussion. This process may lead to the delivery of scuba diving authorizations for selected asthmatic subjects without a higher risk than non-asthmatic subjects.

[Exercise-induced laryngomalacia]. / La laryngomalacie induite par l'exercice.

Exercise-induced laryngomalacia is a rare differential diagnosis of exercise-induced asthma. We report the case of a previously fit 14-year-old female patient who presented with dyspnoea on intense exertion and whose condition had not improved with treatment prescribed for a misdiagnosed exercise-induced asthma. A diagnosis of exercise-induced laryngomalacia was eventually made when a variable extra-thoracic airway obstruction on the flow-volume loops was obtained after an incremental exercise test. Flexible fiberoptic rhinolaryngoscopy confirmed this abnormality and demonstrated an anterior prolapse of the arytenoid region, partially obstructing the airway. The patient therefore underwent laser aryepiglottoplasty which produced a satisfactory anatomical outcome in the larynx but which only resulted in a partial functional improvement. Laryngomalacia is rare and its pathophysiology is not well understood. However, it should be considered in patients presenting with exertional dyspnoea, particularly if there is inspiratory embarrassment, who fail to improve with beta-2-adrenergic agonists. The diagnosis can be made from the flow-volume loop and direct laryngoscopy, before and after exercise.

[Idiopathic pulmonary hemosiderosis and rheumatoid arthritis. Apropos of a case]. / Hémosidérose pulmonaire idiopathique et polyarthrite rhumatoïde. A propos d'une observation.

A 38-year-old woman was known to have had a histologically proven "idiopathic" pulmonary hemosiderosis for 7 years; the authors report the onset in this patient of polyarthralgias with articular swelling and positivity of rheumatoid factor, all features consistent with the diagnosis of rheumatoid arthritis, whose beginning was certainly hidden by steroid therapy. This case, as some others previously published, outlines the possibility of the association of pulmonary hemosiderosis and rheumatoid arthritis: is this a casual association, or may pulmonary hemosiderosis be a rare manifestation of rheumatoid arthritis?

[Physical activity and exercise training for patients with cystic fibrosis]. / Activité physique et réentraînement à l'effort du patient atteint de mucoviscidose.

In France patients with cystic fibrosis benefit from a multidisciplinary follow-up in Cystic Fibrosis Centres. In this follow-up, despite the numerous therapeutic benefits of exercise in this disease, little emphasis is placed on the promotion of physical activity. The aim of this article is to improve this aspect of management, giving advice from a working group of experts, based on the medical literature and clinical experience. These proposals include quantification of physical activity, evaluation of exercise, training and rehabilitation programs and finally, modification of behaviour to include physical activity in the overall cystic fibrosis treatment strategy. It is intended to set up multicentre studies to evaluate the impact of these proposals.

Ventilatory and occlusion-pressure responses to exercise in trained and untrained children.

Pattern of breathing and mouth occlusion pressure were investigated during an incremental and exhaustive ergocycle test in untrained and trained 11 to 13 year old boys. At each level of exercise, the trained group had lower ventilation, a lower respiratory equivalent, and a lower respiratory rate. These results suggest that trained subjects have more efficient ventilation. Lower ventilation coincided with a smaller mean inspiratory flow (VT/TI), while the ratio of inspiratory to total breath (TI/TTOT) was unchanged. In contrast, mouth occlusion pressure and the index of neuromuscular inspiratory drive were the same up to 60 W for the two groups, and tended to be slightly lower in the trained boys above this level.

[Modification of the Hoffmann reflex in function of athletic training (author's transl)]. / Modifications du reflexe de Hoffmann en fonktion de l'entraînement chez le sportif.

The present study measures the values of the Hoffmann reflex and principally the relationship between the maximum reflex response and the maximum direct motor response (H max/M max) and their evolution. The subjects were athletes, performing aerobic and anaerobic type activities, divided into six groups (swimmers; soccer players; tennis players; sprinters; middle and long distance runners; and nonspecific athletes). The results show the average values of the H max/M max (53%) to be not different from those of nonathletes. When separated into aerobic and anaerobic groups, significant differences were found: the values are significantly inferior for subjects participating in anaerobic sports (37%) whereas we found an increase (from 55-75%) in the relationship for swimmers performing aerobic activities after 3 years of regular training. The results suggest, in accordance with previous authors, the possibility of a correlation between the modifications of the H max/M max and the type of activities (aerobic or anaerobic).

[Comparative study of four effort tests on nine-year-old children. The value of systolic tension time (author's transl)]. / Etude comparative de quatre épreuves d'effort chez l'enfant de neuf ans. Intérêt du systolic tension time.

Simple effort tests were carried out on 9-year-old children to measure the systolic tension time (STT) and to judge the accuracy and limitations of such a test by comparing it with other measures more commonly employed in France for the same age group: Pachon-Martinet, Ruffier-Dickson, and maximal oxygen uptake (VO2max), the latter (estimated indirectly) serving as the standard of reference. Subjects stepped onto and off a stool 40 cm high, 24 times per minute; immediately thereafter the heart rate per minute and the arterial systolic pressure (mm Hg) were measured, and the product (the systolic tension time) was obtained. At the age of 9 years, 95% of children have an STT of between 13 000 and 25 000. This test, besides the ease with which it can be performed in daily experimentation, has the advantage of giving results that are at once more precise and more significant than the two standard tests of Pachon-Martinet and Ruffier-Dickson because the quality of the experiment is more satisfactory, because autonomic factors have less impact, and because its discriminative value is higher since only the STT provides a satisfactory correlation with VO2max. The test also fulfills the various requisites of an effort test: it can help to trace a poor cardiovascular response to effort and, because of its selective nature, it can also provide a convenient means of supervision of young athletes. In practice, the test should be complemented by a study of the first 3 min of recovery, as this was the only part of the test showing a difference between boys and girls, whether trained or not.

Extent of lactic anaerobic metabolism in handballers.

The authors investigated lactic anaerobic metabolism in handball players during practice games. Seven players aged 18-21, belonging to second division league clubs, took part in the study. In the laboratory, VO2 max and the onset of blood lactate accumulation (OBLA) were determined with progressive maximal ergocycle tests. On the field, video recordings, cardiotelemetry, and rectal temperature measurements made during the first half of the game were used to quantify exertion. An intravenous catheter worn permanently was used to draw blood for lactate measurements at the 5th, 10th, 15th, 20th, and 30th min of play and after a 10-min rest period. The results confirmed earlier observations showing the need for an excellent maximal aerobic power and capacity in handballers. However, the maximal lactate levels observed (4-9 mmol X l-1) were above those that could be expected from samples drawn only at the end of play. These findings indicate that players must be trained to tolerate high lactate levels to preserve their maximal efficiency throughout the game. Finally, lactate production increased with player exertion and with increasing OBLA.

Isokinetic investigation of knee extensors and knee flexors in young French soccer players.

The knee extensor and knee flexor muscle groups in three groups of young soccer players were tested with a Cybex II isokinetic dynamometer and compared with adults. Muscle strength increased with age. The largest gain was observed in young players aged 16-17 years whose quadriceps was the most modified muscle group giving the lowest H/Q ratio. Analysis of the regression equations obtained for torque values at 30 degrees s-1 and 180 degrees s-1 revealed that there were two distinct groups: under 16 and over 16. After reaching 16 years of age, the increase in muscle strength is greater at low velocity than at high velocity.

[Study of the valuations of serum muscular enzymes and myoglobin after maximal exercise test and during the next 24 hours (author's transl)]. / Etude des variations des taux seriques des enzymes musculaires et de la myoglobine après épreuve d' effort maximale et au cours des 24 heures suivantes.

Twenty-eight male subjects underwent a maximal exercise test on an ergometric bicycle, 13 untrained and 15 trained subjects. At rest and after this maximal exercise, indicated by the increase of the serum lactate and pyruvate acids, venous blood samples were taken to study the release of muscular enzymes (SGOT, SGPT, LDH, alpha HBDH, CPK, CPK MB) and myoglobin in the next 24 h (3 min, 30 min, 8 h and 24 h after the end of this test). The statistic analysis of the results shows significant increases in comparison with the values at rest, according to the enzymes and the groups of subjects, especially for CPK, SGOT, SGPT for which the results are homogeneous with a peak at the 3rd min and the 8th h in the three groups and for HBD and LDH in the groups of trained subjects. However these values remain most often within the normal limits. These results are compared with those of previous works on the same subjects.

[Comparative urinary elimination of caffeine in sedentary and sportsmen after administration of Guronsan]. / Elimination urinaire comparée de la caféine chez le sédentaire et le sportif aprés administration de GURONSAN.

The authors present the results of a study on urinary excretion of caffeine, after a single oral intake of 100 mg of caffeine, in two populations of students at rest and during exercise. Whether expressed in mg/l or mg/g creatinine no significant difference in urinary excretion of caffeine was observed between the two populations and it proves to be lower than the limit level authorized by the IOC (12 mg/l).

[Modalities of the hyperventilation of exercise in maximal triangular effort on the ergometry bicycle in 11-to-13-year-old boys]. / Modalités de l'hyperventilation d'exercice lors d'un effort triangulaire maximal sur bicyclette ergométrique chez des garçons de 11 à 13 ans.

Tidal volume, respiratory frequency, ventilatory equivalent, mean inspiratory flow Vt/Ti, and respiratory timing Ti/Ttot were measured at each level of an incremental exercise in a group of 8 untrained boys. Breathing pattern of the child is characterized by a fast frequency and a small tidal volume. Ventilation at maximal exercise reaches 50% of adults mean value. For the same ventilation, Vt/Ti (when expressed in ml X mn-1 X kg-1) is higher in the child. That suggests a higher central inspiratory activity.

Use of oxygen uptake recovery curve to predict peak oxygen uptake in upper body exercise.

A group of 18 well-trained white-water kayakers performed maximal upper body exercise in the laboratory and during a field test. Laboratory direct peak oxygen uptake (VO2) values were compared, firstly by a VO2 backward extrapolation estimation and secondly by an estimation calculated from VO2 measured during the first 20 s of exercise recovery. Direct peak VO2 correlated with VO2 backward extrapolation (r = 0.89), but the results of this study showed that the backward extrapolation method tended to overestimate significantly peak VO2 by [0.57 (SD 0.31) l.min-1 in the laboratory, and 0.66 (SD 0.33) l.min-1 in the field, P < 0.001]. The VO2 measured during the first 20 s of recovery, whether the exercise was performed in the laboratory or in the field, correlated well with the laboratory direct peak VO2 (r = 0.92 and r = 0.91, respectively). The use of the regression equation obtained from field data (VO2F20s), that is peak VO2 = 0.23 + 1.08 VO2F20s, gave an estimated peak VO2, the mean difference of which compared with direct peak VO2 was 0.22 (SD 0.13) l.min-1. In conclusion, we propose the use of a regression equation to estimate peak VO2 from a single sample of the gas expired during the first 20 s of recovery after maximal exercise involving the upper part of the body.

Long-term nasal intermittent positive pressure ventilation (NIPPV) in sixteen consecutive patients with bronchiectasis: a retrospective study.

Life expectancy and quality of life are poor in patients with chronic respiratory failure due to bronchiectasis. The indication for nocturnal nasal intermittent positive pressure ventilation (NIPPV) remains controversial in chronic obstructive lung disease. The purpose of the present study was to determine whether some of the objectives of home mechanical ventilation, i.e. improvement in blood gas values and reduced length of hospitalization, were fulfilled by NIPPV and oxygen plus medical treatment in patients with chronic respiratory failure due to bronchiectasis. Sixteen consecutive patients (12 females and four males; mean age 57 +/- 11 yrs) with chronic respiratory failure due to bronchiectasis, treated at home with nocturnal NIPPV in addition to oxygen therapy, were retrospectively studied in terms of blood gas values and duration of hospitalization before and after NIPPV. Details of the therapy received by each patient were recorded. Nine patients agreed to complete a questionnaire to determine their perception of the benefits of the treatment. NIPPV was performed using a volumetric respirator and was applied with a customized nasal mask modelled with silicone paste. NIPPV was used for a mean of 26 months (range 0.5-60 months). Eleven patients were alive 12 months after use of NIPPV. No significant improvement in blood gas values was noted on room air during NIPPV, but arterial carbon dioxide tension (Pa,CO2) stabilized after the period of worsening observed before initiation of NIPPV. Duration of hospitalization, the year before and the year after NIPPV, was 19 (3-40) and 16 (8-37) days, respectively (NS). For the 11 patients who were alive 2 yrs after the start of NIPPV, duration of hospitalization the year before NIPPV and between 12 and 24 months after NIPPV were 17 (4-40) and 7 (2-27) days, respectively (p < 0.05). Nine patients who had received NIPPV for at least 12 months at the time of the study reported an improvement in their quality of life. The results suggest that home ventilatory support by nasal intermittent positive pressure ventilation offers an acceptable alternative to tracheotomy, with less discomfort, in the management of severe respiratory failure due to bronchiectasis, in order to allow the patient to return home. These results should be confirmed by controlled studies.