Respiratory muscle training and exercise ventilation while diving at altitude.

Introduction: Pre-dive altitude exposure may increase respiratory fatigue and subsequently augment exercise ventilation at depth. This study examined pre-dive altitude exposure and the efficacy of resistance respiratory muscle training (RMT) on respiratory fatigue while diving at altitude. Methods: Ten men (26±5 years; VO2peak: 39.8±3.3 mL• kg-1•min-1) performed three dives; one control (ground level) and two simulated altitude dives (3,658 m) to 17 msw, relative to ground level, before and after four weeks of resistance RMT. Subjects performed pulmonary function testing (e.g., inspiratory [PI] and expiratory [PE] pressure testing) pre- and post-RMT and during dive visits. During each dive, subjects exercised for 18 minutes at 55% VO2peak, and ventilation (VE), breathing frequency (ƒb,), tidal volume (VT) and rating of perceived exertion (RPE) were measured. Results: Pre-dive altitude exposure reduced PI before diving (p=0.03), but had no effect on exercise VE, ƒb, or VT at depth. At the end of the dive in the pre-RMT condition, RPE was lower (p=0.01) compared to control. RMT increased PI and PE (p<0.01). PE was reduced from baseline after diving at altitude (p<0.03) and this was abated after RMT. RMT did not improve VE or VT at depth, but decreased ƒb (p=0.01) and RPE (p=0.048) during the final minutes of exercise. Conclusion: Acute altitude exposure pre- and post-dive induces decrements in PI and PE before and after diving, but does not seem to influence ventilation at depth. RMT reduced ƒb and RPE during exercise at depth, and may be useful to reduce work of breathing and respiratory fatigue during dives at altitude.

Differences in Respiratory Muscle Responses to Hyperpnea or Loaded Breathing in COPD.

INTRODUCTION: We aimed to compare acute mechanical and metabolic responses of the diaphragm and rib cage inspiratory muscles during two different types of respiratory loading in patients with chronic obstructive pulmonary disease. METHODS: In 16 patients (age, 65 ± 13 yr; 56% male; forced expiratory volume in the first second, 60 ± 6%pred; maximum inspiratory pressure, 82 ± 5%pred), assessments of respiratory muscle EMG, esophageal pressure (Pes) and gastric pressures, breathing pattern, and noninvasive assessments of systemic (V˙O2, cardiac output, oxygen delivery and extraction) and respiratory muscle hemodynamic and oxygenation responses (blood flow index, oxygen delivery index, deoxyhemoglobin concentration, and tissues oxygen saturation [StiO2]), were performed during hyperpnea and loaded breathing. RESULTS: During hyperpnea, breathing frequency, minute ventilation, esophageal and diaphragm pressure-time product per minute, cardiac output, and V˙O2 were higher than during loaded breathing (P < 0.05). Average inspiratory Pes and transdiaphragmatic pressure per breath, scalene (SCA), sternocleidomastoid, and intercostal muscle activation were higher during loading breathing compared with hyperpnea (P < 0.05). Higher transdiaphragmatic pressure during loaded breathing compared with hyperpnea was mostly due to higher inspiratory Pes (P < 0.05). Diaphragm activation, inspiratory and expiratory gastric pressures, and rectus abdominis muscle activation did not differ between the two conditions (P > 0.05). SCA-blood flow index and oxygen delivery index were lower, and SCA-deoxyhemoglobin concentration was higher during loaded breathing compared with hyperpnea. Furthermore, SCA and intercostal muscle StiO2 were lower during loaded breathing compared with hyperpnea (P < 0.05). CONCLUSION: Greater inspiratory muscle effort during loaded breathing evoked larger rib cage and neck muscle activation compared with hyperpnea. In addition, lower SCA and intercostal muscle StiO2 during loaded breathing compared with hyperpnea indicates a mismatch between inspiratory muscle oxygen delivery and utilization induced by the former condition.

Effects of Sprint-Interval and Endurance Respiratory Muscle Training Regimens.

INTRODUCTION: Recently a novel, time-saving respiratory muscle sprint-interval training (RMSIT) was developed. To test the extent to which RMSIT improves respiratory muscle performance compared with a conventional respiratory muscle endurance training (RMET), a novel incremental respiratory muscle test (IncRMT), loading inspiratory and expiratory muscles, was designed to assess performance changes associated with respiratory muscle training (RMT). METHODS: Healthy, moderately trained males and females (age: 26 ± 5 yr, V˙O2peak: 47 ± 12 mL·min·kg) were randomized and balanced to three groups (RMSIT 5m/5f; RMET 6m/6f; PLAT 5m/6f). Lung function, respiratory muscle strength, and IncRMT performance were tested before and after 1 month of RMT. During the IncRMT, muscle activity and muscle deoxygenation were assessed via surface EMG and near-infrared spectroscopy of sternocleidomastoid (STERNO), intercostal (INTER), and abdominal (ABDO) muscles. RESULTS: Two-way ANOVA revealed a main effect of training for increased maximal voluntary ventilation (P = 0.001) and maximal inspiratory pressure (P = 0.017). Both RMT groups increased work of breathing during training sessions to the same extent (RMSIT: +17.4 ± 8.9 kJ; RMET: +26.2 ± 16.1 kJ; P = 0.143) with a larger increase in average mouth pressure in RMSIT (RMSIT: +20.0 ± 15.0 cm H2O; RMET: +3.3 ± 1.5 cm H2O; P = 0.001). After training, IncRMT duration increased in both RMT groups compared with PLAT (RMSIT: +5.6 ± 2.1 min, P = 0.0006 vs PLAT; RMET: +3.8 ± 4.2 min, P = 0.020 vs PLAT). At similar work, only INTER activity during inspiration increased after RMET. Higher performance after RMSIT was associated with higher activity in STERNO and ABDO, but after RMET, STERNO, INTER, and ABDO showed higher activity. CONCLUSION: One month of RMSIT and RMET shows similar improvements in respiratory muscle performance despite different duration of training sessions. Also, muscular adaptations might differ.

The Effects of Prone with Respect to Supine Position on Stress Relaxation, Respiratory Mechanics, and the Work of Breathing Measured by the End-Inflation Occlusion Method in the Rat.

PURPOSE: The working hypothesis is that the prone position with respect to supine may change the geometric configuration of the lungs inside the chest wall, thus their reciprocal mechanical interactions, leading to possible effects on stress relaxation phenomena and respiratory mechanics. METHOD: The effects of changing body posture from supine to prone on respiratory system mechanics, particularly on stress relaxation, were investigated in the rat by the end-inflation occlusion method. RESULTS: In the prone with respect to supine position, an increment of the frictional resistance of the airway (from 0.13 ± 0.01 to 0.19 ± 0.02 cm H2O/l sec(-1), p < 0.05) and a decrement of the stress relaxation-linked pressure dissipation (from 0.51 ± 0.05 to 0.45 ± 0.05 cm H2O/l sec(-1), p < 0.01) were found. Respiratory system elastance and total resistive pressure dissipation did not change significantly. Accordingly, a significant increase of the frictional "ohmic" mechanical inspiratory work of breathing and a decrease of the visco-elastic work of inspiration were demonstrated, while no significant changes occurred for the total mechanical work of breathing and its total resistive and elastic components. CONCLUSION: It is concluded that postural changes affect the visco-elastic characteristics of the respiratory system and the related stress relaxation phenomena by influencing the disposition and relation of the lungs inside the chest wall and their relative geometrical configuration, and the interaction phenomena of the constitutive parenchymal structures, i.e., elastin and collagen fibers. Since the prone position resulted in no serious or disadvantageous respiratory system mechanical derangement, it is suggested it may be usefully applied in nursing or for therapeutic goals.

Flow resistance, work of breathing of humidifiers, and endotracheal tubes in the hyperbaric chamber.

Humidification of inspired gas is critical in ventilated patients, usually achieved by heat and moisture exchange devices (HMEs). HME and the endotracheal tube (ETT) add airflow resistance. Ventilated patients are sometimes treated in hyperbaric chambers. Increased gas density may increase total airway resistance, peak pressures (PPs), and mechanical work of breathing (WOB). We tested the added WOB imposed by HMEs and various sizes of ETT under hyperbaric conditions. We mechanically ventilated 4 types of HMEs and 3 ETTs at 6 minute ventilation volumes (7-19.5 L/min) in a hyperbaric chamber at pressures of 1 to 6 atmospheres absolute (ATA). Peak pressure increased with increasing chamber pressure with an HME alone, from 2 cm H2O at 1 ATA to 6 cm H(2)O at 6 ATA. Work of breathing was low at 1 ATA (0.2 J/L) and increased to 1.2 J/L at 6 ATA at minute ventilation = 19.5 L/min. Connecting the HME to an ETT increased PP as a function of peak flow and chamber pressure. Reduction of the ETT diameter (9 > 8 > 7.5 mm) and increase in chamber pressure increased the PP up to 27.7 cm H2O, resistance to 33.2 cmH2O*s/L, and WOB to 3.76 J/L at 6 ATA with a 7.5-mm EET. These are much greater than the usually accepted critical peak pressures of 25 cm H2O and WOB of 1.5 to 2.0 J/L. Endotracheal tubes less than 8 mm produce significant added WOB and airway pressure swings under hyperbaric conditions. The hyperbaric critical care clinician is advised to use the largest possible ETT. The tested HMEs add negligible resistance and WOB in the chamber.

Respiratory muscle training reduces the work of breathing at depth.

Resistance respiratory muscle training (RRMT) increases respiratory muscle and swimming performance at depths down to 17 msw. It is unknown if RRMT improves swimming performance at greater depths and if the improvements are associated with a reduced work of breathing (WOB), altered respiratory mechanics and/or improved respiratory muscle performance. Eight male subjects (30.3 +/- 6.0 years) were tested swimming underwater in a hyperbaric chamber at 37 m of depth against a pre-determined load (70% VO(2)) until exhausted. End expiratory lung volume (EELV) was determined by subtracting inspiratory capacity from total lung capacity throughout the swims. The mechanical WOB on the lung was calculated as the integrated product of the transpulmonary pressure and ventilatory flow. Maximal expiratory (P EMAX) and inspiratory pressures (P IMAX) were measured pre- and post-RRMT. RRMT was performed every 30 s against spring loaded inspiratory and expiratory valves 30 min/day, 5 days/week, for 4 weeks. RRMT increased P (IMAX) and P (EMAX) by 40% (110 +/- 11 cmH2O (SD) vs. 155 +/- 22, p < 0.001) and 30% (148 +/- 33 cmH2O vs. 192 +/- 49, p < 0.001), respectively, respiratory endurance by 75% (19.7 +/- 15.4 min vs. 34.4 +/- 27.3, p = 0.010), and swimming endurance by 87% (26.4 +/- 9.7 min vs. 49.4 +/- 21.6, p = 0.004). The longer swimming time was associated with reduced V(E) and V(A) (p < 0.001), f(b) (p < 0.001), V(CO(2)) (p < 0.001) and WOB (p < 0.001). There were no changes in EELV post-RRMT. These results suggest the improved exercise performance post-RRMT was associated with stronger respiratory muscles, a decreased f b, and a reduced WOB.

Dysphagia and nutrition problems in infants with apert syndrome.

OBJECTIVE: The purpose of this study was to identify and describe the nature of dysphagia and nutrition difficulties in infants with Apert syndrome. DESIGN: The study comprised a review of the medical, nutrition, and feeding records of 13 consecutive infants still feeding by the bottle who had been referred to the Craniofacial Unit and analyses of swallow function from videofluoroscopic swallow investigations. MAIN OUTCOME MEASURES: Outcome measures included qualitative analyses of bottle-feeding and nutritional status and quantitative functional severity ratings of dysphagia based on videofluoroscopic swallow investigations using the O'Neil et al. (1999) Dysphagia Outcome Severity Scale. RESULTS: The main qualitative descriptors of oral feeding in this cohort included uncoordinated suck-swallow-breathe patterns, inability to maintain sucking bursts, and changes in respiratory patterns as the feed progressed. Videofluoroscopic evaluations (N = 7) showed silent laryngeal penetration or aspiration in more than half of the cohort. Failure to thrive was a frequent occurrence seen in seven infants, and 9 of the 10 required dietetic intervention and enteral supplements. (Nutritional records were not located for three infants.) CONCLUSIONS: In view of the small sample size and retrospective nature of the study, the results need to be interpreted with caution. However, the study adds to current limited knowledge on feeding and nutrition in Apert syndrome. Further prospective multidisciplinary and objective research is clearly warranted.

Patients with acute spinal cord injury benefit from normocapnic hyperpnoea training.

BACKGROUND: Functional loss of respiratory muscles in persons with spinal cord injury leads to impaired pulmonary function and respiratory complications. In addition, respiratory complications are responsible for 50-67% of the morbidity in this population. OBJECTIVE: To investigate the effects of normocapnic hyperpnoea training in acute spinal cord injury. PATIENTS AND METHODS: Fourteen patients were randomized between control (sham) and an experimental normocapnic hyperpnoea training group. Vital capacity, maximal voluntary ventilation, respiratory muscle strength and endurance, respiratory complications and symptoms were evaluated before, after 4 and 8 weeks of training and after 8 weeks follow-up. RESULTS: Maximal voluntary ventilation, respiratory muscle strength and endurance improved significantly in the experimental group compared with the control group (p < 0.05). Improvements in vital capacity tended to be different from the control group at 8 weeks of training. The Index of Pulmonary Dysfunction decreased after 4 weeks of training and respiratory complications were reported less frequently in the experimental group compared with the control group. CONCLUSION: Normocapnic hyperpnoea training in patients with spinal cord injury improved respiratory muscle strength and endurance. Respiratory complications occurred less frequently after training.

Optimal intensity for respiratory muscle endurance training in patients with spinal cord injury.

OBJECTIVE: Respiratory muscle endurance of able-bodied persons, assessed by normocapnic hyperpnoea at 70% of their maximal voluntary ventilation, usually ranges from 10 to 20 minutes. The aim of this study was to determine the level of ventilation that patients with paraplegia and tetraplegia can sustain for 10-20 minutes to later be used as the guideline for respiratory muscle endurance training. DESIGN: Pilot study; cross-over setting. SUBJECTS: Two groups, 8 patients with paraplegia and 6 with tetraplegia. METHODS: Respiratory muscle endurance tests were performed at 3 different intensities of normocapnic hyperpnoea, i.e. 20%, 40% and 60% maximal voluntary ventilation. Subjects performed partial re-breathing from a bag to assure normocapnia. Respiratory endurance was separately analysed for patients with paraplegia and tetraplegia. RESULTS: Mean respiratory endurance times were 46.0, 18.9 and 4.2 minutes at 20%, 40% and 60% maximal voluntary ventilation in patients with tetraplegia and 51.8, 38.8 and 12.2 minutes in patients with paraplegia. The duration differed significantly at 60% maximal voluntary ventilation between the groups. CONCLUSION: Minute ventilation to perform respiratory muscle endurance training can be set at around 40% of maximal voluntary ventilation for patients with tetraplegia and around 60% of maximal voluntary ventilation for patients with paraplegia, as these levels can be sustained for 10-20 minutes.

Training to yoga respiration selectively increases respiratory sensation in healthy man.

Because yoga practitioners think they are benefiting from their breath training we hypothesized that yoga respiration training (YRT) could modify the respiratory sensation. Yoga respiration (YR) ("ujjai") consisted of very slow, deep breaths (2-3 min(-1)) with sustained breath-hold after each inspiration and expiration. At inclusion in the study and after a 2-month YRT program, we determined in healthy subjects their eupneic ventilatory pattern and their capacity to discriminate external inspiratory resistive loads (respiratory sensation), digital tactile mechanical pressures (somesthetic sensation) and sound-pressure stimulations (auditory sensation). Data were compared to a gender-, age-, and weight-matched control group of healthy subjects who did not undergo the YRT program but were explored at the same epochs. After the 2-month YRT program, the respiratory sensation increased. Thus, both the exponent of the Steven's power law (Psi=kPhin) and the slope of the linear-linear plot between Psi and mouth pressure (Pm) were significantly higher, and the intercept with ordinate axis of the Psi versus Pm relationship was lower. After YRT, the peak Pm developed against inspiratory loads was significantly lower, reducing the load-induced activation of respiratory afferents. YRT induced long-lasting modifications of the ventilatory pattern with a significant lengthening of expiratory duration and a modest tidal volume increase. No significant changes in somesthetic and auditory sensations were noted. In the control group, the respiratory sensation was not modified during a 15-min period of yoga respiration, despite the peak Pm changes in response to added loads were then significantly reduced. These data suggest that training to yoga respiration selectively increases the respiratory sensation, perhaps through its persistent conditioning of the breathing pattern.

Resistive inspiratory muscle training in sleep-disordered breathing of traumatic tetraplegia.

OBJECTIVE: To assess the effect of resistive inspiratory muscle training (RIMT) on the static pulmonary function and sleep-induced breathing disorder of individuals with chronic cervical cord injury. DESIGN: Before-after training. SETTING: Home-setting training program. PATIENTS: Fourteen complete traumatic tetraplegic patients (12 men, 2 women; mean age, 41.1 +/- 14y; range, 19-56y) injured for more than 6 months. INTERVENTION: Subjects participated in a 6-week RIMT program for 15 minutes twice daily at a training intensity of 60% of maximum inspiratory pressure (MIP). The participants were reevaluated at the end of 6-week training. MAIN OUTCOME MEASURES: Lung volume, peak expiratory flow (PEF), MIP, and maximum expiratory pressure (MEP) were measured by using a spirometry and inspiratory force meter, respectively. Capnography was used to monitor nocturnal pulse oxyhemoglobin saturation (SpO(2)) and end-tidal carbon dioxide tension level (ETCO(2)) of the patients. RESULTS: The maximum voluntary ventilation (MVV) and MIP of individuals with chronic cervical cord injury substantially improved after RIMT. MIP increased from -68.7 +/- 27.4cmH(2)O to -77.3 +/- 24.0cmH(2)O and MVV rose from 62.7 +/- 33.2L to 73.4 +/- 31.3L (P <.05). Despite increasing from 3.5 +/- 1.8L/s to 4.0 +/- 1.7L/s, PEF was statistically insignificant. For the individuals with improved MIP, the duration of ETCO(2) greater than 48mmHg reduced from 2.2% +/- 3.3% to 1.0% +/- 2.0% of total sleep time (P =.05) and that of SpO(2) less than 90% significantly declined from 1.8% +/- 2.8% to 1.3% +/- 2.4% of total sleep time (P <.05). CONCLUSION: These findings suggest that RIMT can enhance the respiratory muscle strength and endurance of chronic tetraplegia and further ameliorate the sleep-induced breathing disorder. Therefore, RIMT is suggested as a home program for patients with sleep-disordered breathing.

Uso del indice kinésico de la carga de trabajo ventilatorio en el Area de Gestión Clínica del niño del Hospital Padre Hurtado / Use of kinesic index of the ventilatory task load in children clinical gestion area at Hospital Padre Hurtado

Se realizó una experiencia valorativa a través de un Indice Kinésico de la Carga de trabajo Ventilatorio en el Area de Gestión Clínica del Niño del Hospital Padre Hurtado. Para esto se trabajó con dos grupos de pacientes. El Grupo 1 conformado por niños portadores de Enfermedad Respiratoria y el Grupo 2, constituído por niños sin Enfermedad Respiratoria. Con el Grupo 1 se realizó comparación de valores a través del Indice Kinésico de la Carga de Trabajo Ventilatorio entre distintos Kinesiólogos y con el Grupo 2 se estableció un criterio de corte para prescindir de Kinesiterapia Respiratoria empleando este índice. En el Grupo 1 se ejecutaron 88 evaluaciones y en el Grupo 2 se realizaron 55 evaluaciones, desde Enero a Marzo del año 2000. Los resultados demostraron que no existen diferencias significativas entre los valores del Indice Kinésico de la Carga de Trabajo Ventilatorio obtenidos por dos kinesiólogos diferentes simultáneamente (p < 0.01). además el puntaje de corte de acuerdo al índice se estableció de 3.0 puntos con una desviación estandar de 1.76. Se discuten y concluyen aspectos derivados del uso de metodologías para caracterizar, jerarquizar y orientar la actividad profesional del kinesiólogo que se desempeña en el área respiratoria intrahospitalaria básica

[Changes in body equilibrium response caused by breathing. A posturographic study with visual feedback]. / Veränderungen von Körpergleichgewichtsreaktionen durch Atemarbeit. Eine posturographische Studie unter Einbeziehung des visuellen Feedback.

BACKGROUND: Therapeutical methods involving holistic medicine are of increasing interest. The present study deals with the psychophysical breath work by Middendorf and examines whether it has an effect on reactions of the body's equilibrium system. METHODS: Different optical patterns were projected on a video screen to the test subject standing on a modified posturographic platform. Subjects were instructed to shift their center of gravity according to the patterns projected on the video screen. The patterns consisted of a line that had to be followed in the anterior-posterior and in the lateral plane, and of a circle which had to be followed clockwise and counterclockwise. PATIENTS: Three groups each consisting of 17 healthy persons were tested; group 1: advanced in breath training, group 2: beginners in breath training, group 3: no experience in breath work at all. RESULTS: Group 1 und 2 show significantly better results in the posturographic test with visual feedback than subjects without experience in breast work (group 3). Furthermore, posturographic results immediately after one hour of breath work reveal clear improvements in the body equilibrium. CONCLUSIONS: Psychophysical breath work by Middendorf leads to a general improvement of the body equilibrium which is stable over time. The positive results of this study lead to the assumption that breath work by Middendorf is a valuable method for treatment and rehabilitation of balance disorders.

[Ventilator weaning after long-term ventilation--the concept of a regional ventilator weaning center]. / Entwöhnung vom Respirator nach Langzeitbeatmung--Das Konzept eines regionalen Entwöhnungszentrums.

Long-term mechanical ventilation implies a significant number of weaning failures. The basis of this unweanability is chronic fatigue of the inspiratory muscles which is due to depletion of energy store (e.g. glycogen). Considering this pathophysiological principle, the decisive therapeutic option during weaning from long-term mechanical ventilation consists of resting the respiratory muscles. The commonly used assisted ventilation modes only partially relieve the respiratory muscles because the work of breathing is done both during the trigger phase and during the inspiratory cycle. The essential characteristic of our weaning concept includes the repeated determination of the spontaneous breathing frequency in awake patients, which is followed by controlled intermittent positive pressure ventilation with a slightly higher respiratory rate. Ideally, this results in total suppression of the activity of the breathing centre, and in subsequent relief and recovery of the respiratory muscles by replenishing the energy stores. The close succession of relief and training periods avoids inactivity-induced atrophy of the respiratory muscles and permits regeneration. Additionally, our weaning concept avoids increases in inspiratory work during the phases of spontaneous breathing. This means that high-resistance small-caliber endotracheal tubes have to be replaced by large tubes. Moreover, transtracheal oxygen insufflation during spontaneous breathing decreases anatomic dead space. This reduces minute ventilation and, therefore, the work of breathing. In patients still exhibiting chronic fatigue of the respiratory muscle pump after successful weaning, intermittent home ventilation is initiated via a breathing mask. Apart from the concept described above, successful weaning from the respirator after long-term ventilation is based upon dedicated patient care and depends on the architectural characteristics of the intensive care unit.

Effects of abdominal and thoracic breathing upon multiple-site electromyography and peripheral skin temperature.

Peripheral finger temperature, frontalis and upper trapezius EMG, and self-report of arousal were assessed for four subjects during abdominal and thoracic breathing in a single-subject reversal design. Two subjects displayed significant differences between abdominal and thoracic breathing conditions; one for frontalis EMG, trapezius EMG, and self-report of arousal and one for trapezius EMG. Two subjects showed no significant effects. All subjects reached performance criteria during training sessions. Abdominal breathing performance during reversals was 100% and 92% of sampled breath cycles for the two subjects who showed significant change, and 65% and 42% for the two subjects who showed none. Methodological issues for measurement of breathing patterns and peripheral skin temperature are discussed.

Respiratory muscle limitation in patients after pneumonectomy.

Exercise capacity is significantly impaired in postpneumonectomy patients who have relatively normal remaining lungs. Our objectives are to determine (1) the nature and extent of mechanical ventilatory abnormalities and oxygen cost of breathing in such patients, and (2) the efficacy of a selective respiratory muscle training program in improving ventilatory and exercise performance. A group of eight postpneumonectomy and eight normal subjects (mean ages 59 and 50 yr, respectively) were studied during steady-state exercise and resting voluntary hyperventilation. Ventilation, work of breathing, cardiac output, and oxygen costs of breathing were determined. Four postpneumonectomy and five normal subjects were studied before and after a respiratory muscle training program. In patients after pneumonectomy compared with normal control subjects, maximal oxygen uptake (VO2) was 56% lower (p < 0.001). Work of breathing was significantly higher at a given ventilation. Mechanical efficiency of ventilation was lower by 44% (p < 0.05). Near maximal VO2, 48% of any additional increment of total-body VO2 was required to sustain the associated increment in ventilatory work, compared with 28% in normal subjects (p < 0.05), suggesting that competition between respiratory and nonrespiratory muscles for oxygen delivery is a significant factor limiting exercise after pneumonectomy. After respiratory muscle training, maximal respiratory pressures improved but maximal sustained ventilation and maximal VO2 did not improve significantly, suggesting that selective respiratory muscle training is of limited utility in postpneumonectomy patients.