Glossopharyngeal pistoning for lung insufflation in patients with cervical spinal cord injury.

STUDY DESIGN: A prospective cohort study. OBJECTIVES: To evaluate whether patients with cervical spinal cord injury (CSCI) are able to learn the technique of glossopharyngeal pistoning (breathing) for lung insufflation (GI) and if learned, to evaluate the effects of GI on pulmonary function and chest expansion after 8 weeks. SETTING: Karolinska University Hospital, Stockholm, Sweden. METHODS: Twenty-five patients with CSCI (21 men, four women) with a mean age of 46 years (21-70), from the Stockholm area, were used in this study. The participants performed 10 cycles of GI four times a week, for 8 weeks. Pulmonary function tests made before and after the GI training included vital capacity (VC), expiratory reserve volume (ERV), functional residual capacity (FRC; measured with nitrogen washout), residual volume (RV) and total lung capacity (TLC). Chest expansion was measured before and after training. RESULTS: Five of the twenty-five participants had difficulty in performing GI and were excluded in further analysis. Performing a GI maneuvre increased participants' VC on average by 0.88+/-0.5 l. After 8 weeks of training, the participants had significantly increased their VC 0.23 l, (P<0.001), ERV 0.16 l, (P<0.01), FRC 0.86 l, (P<0.001), RV 0.70 l, (P<0.001) and TLC 0.93 l, (P<0.001). Chest expansion increased at the level of the xiphoid process by 1.2 cm (P<0.001) and at the level of the fourth costae by 0.7 cm (P<0.001). CONCLUSIONS: After using GI for a period of 8 weeks, the participants with CSCI who could perform GI were able to improve pulmonary function and chest expansion.

Polysomnography in chronic neuromuscular disease.

BACKGROUND: Sleep is a risk factor for respiratory failure in patients with chronic neuromuscular diseases (NMD). OBJECTIVE: To explore the diagnostic value of monitoring sleep parameters in addition to nocturnal respiratory parameters. METHODS: Thirty-one patients with chronic NMD underwent whole-night polysomnograms including EMG from accessory respiratory muscles. RESULTS: Sleep macrostructure was normal on average. The number of respiratory arousals per hour of sleep was above the upper limit observed in a control group (>2.1) in 71% of the patients, but was moderate in most cases. Nadir oxygen saturation <85% was the most common finding indicating respiratory dysfunction and was present in 80% of the patients. Noninvasive blood gas monitoring identified all but 2 patients with respiratory-induced sleep abnormalities. The respiratory arousal rate was correlated with the oxygen desaturation index, but otherwise there were no significant correlations between sleep and nocturnal respiratory parameters. Vital capacity was significantly positively correlated with obstructive apnea index and daytime base excess to nadir oxygen saturation. Inspiratory activity in accessory respiratory muscles was present during REM sleep and/or slow wave sleep in 70% of the patients. CONCLUSION: The severity of nocturnal respiratory dysfunction is not reflected in the extent of sleep impairment in patients with chronic neuromuscular diseases.

Lung clearance in children with Duchenne muscular dystrophy or spinal muscular atrophy with and without CPAP (continuous positive airway pressure).

Bronchiolar clearance was studied in 7 boys in the age range of 8 to 17 years, 6 with Duchenne muscular dystrophy (DMD) and 1 with spinal muscular atrophy type II (SMA-II). These boys had healthy lungs but a severely reduced muscular strength (wheelchair dependent). In 6 of the boys, clearance was studied twice, at one occasion as a control and at the other occasion following treatment with continuous positive airway pressure (CPAP). A control group of healthy adults was used. In the clearance examinations, 6-microm Teflon particles, labeled with III In was inhaled extremely slowly, 0.05 L/s. This gives a deposition mainly in the bronchioles. Lung retention was measured after 0,24,48, and 72 hours. A model for deposition of particles in the adult lung was scaled down to represent the children in this study. Deposition in various airway generations was calculated to be similar in children and adults. Also the measured retentions were similar in the boys and the adults. In the clearance experiments during CPAP treatment, there was a significantly lower retention after 72 hours (but not after 24 and 48 hours) than in the control experiments. Theresults indicate that a severe reduction of muscular strength, and thereby a reduction of mechanical movement of the lung, does not affect clearance from large and small airways. However, some effect of clearance from small airways cannot be excluded due to the short measuring period. The small but significant effect of the CPAP treatment might have potential clinical importance and suggest that bronchiolar clearance can be affected by some form of mechanical force.

Inspiratory muscle training in patients with prior polio who use part-time assisted ventilation.

OBJECTIVE: To evaluate whether inspiratory muscle training in patients with prior poliomyelitis (and with symptoms and signs of hypoventilation) who use part-time assisted ventilation could improve symptoms and respiratory muscle function without adverse effects. DESIGN: Intervention study with before-after trial. SETTING: Training was performed in the patients' homes; assessments were performed at the hospital. PATIENTS: Ten prior-polio patients were included. Three of them did not complete the trial, and their data were not included in results of training. INTERVENTION: Ten weeks of daily inspiratory muscle training. MAIN OUTCOME MEASURES: Spirometry, maximal inspiratory and expiratory pressures, inspiratory muscle endurance, and questions regarding activities of daily living were performed. RESULTS: Inspiratory endurance capacity over 5 minutes improved from 10.7 to 16.7cm H2O (p < .05) assessed at 15 on the Borg scale, and most patients improved in activities of daily living. The whole-body endurance capacity remained stable over the studied period. CONCLUSION: Inspiratory muscle training and close supervision can increase respiratory muscle endurance and improve well-being in patients with prior polio who use part-time assisted ventilation.

Obstructive sleep apneas in relation to severity of cervical spinal cord injury.

Thirty-three subjects (28 men, five women) with complete or incomplete cervical cord injury representing a wide range of neurological impairment were investigated with regard to the prevalence of Obstructive Sleep Apnea (OSA). The relation between OSA and neurological function, respiratory capacity, body mass index and symptoms associated with OSA were studied. Overnight sleep recordings employed combined oximetry and respiratory movement monitoring. Pulmonary function tests included static and dynamic spirometry, maximal static inspiratory and expiratory pressures at the mouth. The subjects answered a questionnaire concerning sleep quality and tiredness. The prevalence of OSA was 15% (5/33) in this nonobese cervical cord injury study population. Nine percent of the subjects (3/33) fulfilled the criteria for obstructive sleep apnea syndrome, but daytime sleepiness or fatigue were also common in subjects without OSA. There was an inverse correlation between oxygen desaturation index and American Spinal Injury Association (ASIA) motor score in the subjects with complete injury, while there was no such correlation in the whole study group. There were significant correlations between maximal inspiratory and expiratory pressures and vital capacity and between ASIA motor score and vital capacity.

Oxygen desaturations during exercise and sleep in fit tetraplegic patients.

OBJECTIVE: Tetraplegic patients are particularly at risk for respiratory deficiencies during sleep. In a previous study, it was found that several patients exhibited significant oxygen desaturations during arm ergometry tests. Therefore, the issue of whether patients who desaturate during exercise would be especially at risk for having nocturnal respiratory problems was raised. DESIGN: Respiratory recordings in connection with arm ergometry tests and during sleep. SETTING: Arm ergometry tests were performed in a hospital laboratory, and sleep recordings were performed in the patients' homes. PATIENTS: Nine C5-C6 tetraplegic patients, aged 22 to 42 years with body mass index of 15.2 to 24.2 kg/m2. MAIN OUTCOME MEASURES: Oximetry during exercise and sleep and sleep recordings. RESULTS: During exercise, six patients desaturated 6% to 20%. Only one patient had signs of a significant nocturnal respiratory problem with an average of eight desaturations per hour of sleep and an obstructive respiration movement pattern. Two additional patients (with normal oximetry during exercise) showed occasional desaturation below 89% during rapid eye movement sleep. CONCLUSION: In this study, the majority of tetraplegic patients desaturated during submaximal arm exercise but not during sleep. The reason could be that the patients in this study were all lean and physically active, which is at variance with previously published sleep studies.

The effect of trunk support on performance during arm ergometry in patients with cervical cord injuries.

Earlier studies have shown that the diaphragm might have a postural function that could interfere with its respiratory function during arm cycling in patients with cervical cord injuries with impaired elbow extension. The purpose of this study was to evaluate the effect of trunk support on working performance in such patients. Ten patients with low-cervical-cord injuries performed an arm ergometer test without and with trunk support with at least one week between the tests. The work load averaged 30 (20-50) Watt. Oxygen uptake at steady state averaged 0.71 +/- 0.09 l/min without trunk support and 0.64 +/- 0.10 l/min with trunk support, P < 0.05. There was no difference in blood lactate without or with trunk support. Maximum performance time averaged 8.3 +/- 4.3 min without trunk support and 19.5 +/- 8.8 min with trunk support, P < 0.01. Oxygen saturation tended to decrease during work and returned to resting values after termination. This study showed that trunk support during arm ergometry in cervical-cord-injury patients with impaired elbow extension decreased the energy cost during sub-maximal work and increased the time to perform work. The results indicate that trunk stabilisation might improve performance of activities of daily living and that it should also be considered during exercise affecting the postural balance of these patients.

A new nasal mask for nocturnal home ventilation in chronic neuromuscular disorders.

A new nasal mask for nocturnal, intermittent positive pressure ventilation was used by patients with symptomatic sleep hypoventilation due to chronic neuromuscular disorders. The custom-fabricated mask is cast in visible light curing acrylic from a plaster model. Air is delivered through plastic tubes cast in the mask. The treatment was introduced through close cooperation between a physiotherapist and a technician. Evaluation was performed after 4-34 months' regular use. The mask was well tolerated. All patients reported comfortable sleep and symptom relief. The effectiveness was confirmed by whole-night measurements of oxygen saturation and end-tidal carbon dioxide.