Maximum Insufflation Capacity Research Articles

A Randomized Controlled Clinical Trial of Lung Volume Recruitment in Adults with Neuromuscular Disease.

Rationale: Clinical care guidelines advise that lung volume recruitment (LVR) be performed routinely by people with neuromuscular disease (NMD) to maintain lung and chest wall flexibility and slow lung function decline. However, the evidence base is limited, and no randomized controlled trials of regular LVR in adults have been published. Objectives: To evaluate the effect of regular LVR on respiratory function and quality of life in adults with NMD. Methods: A randomized controlled trial with assessor blinding was conducted between September 2015 and May 2019. People (>14 years old) with NMD and vital capacity <80% predicted were eligible, stratified by disease subgroup (amyotrophic lateral sclerosis/motor neuron disease or other NMDs), and randomized to 3 months of twice-daily LVR or breathing exercises. The primary outcome was change in maximum insufflation capacity (MIC) from baseline to 3 months, analyzed using a linear mixed model approach. Results: Seventy-six participants (47% woman; median age, 57 [31-68] years; mean baseline vital capacity, 40 ± 18% predicted) were randomized (LVR, n = 37). Seventy-three participants completed the study. There was a statistically significant difference in MIC between groups (linear model interaction effect P = 0.002, observed mean difference, 0.19 [0.00-0.39] L). MIC increased by 0.13 (0.01-0.25) L in the LVR group, predominantly within the first month. No interaction or treatment effects were observed in secondary outcomes of lung volumes, respiratory system compliance, and quality of life. No adverse events were reported. Conclusions: Regular LVR increased MIC in a sample of LVR-naive participants with NMD. We found no direct evidence that regular LVR modifies respiratory mechanics or slows the rate of lung volume decline. The implications of increasing MIC are unclear, and the change in MIC may represent practice. Prospective long-term clinical cohorts with comprehensive follow-up, objective LVR use, and clinically meaningful outcome data are needed. Clinical trial registered with anzctr.org.au (ACTRN12615000565549).

Effects of Rehabilitative Intervention for Augmenting Cough Function in Patients with Multiple System Atrophy.

One of the causes of death in patients with multiple system atrophy (MSA) is aspiration pneumonia caused by cough dysfunction. This study aimed to identify an effective approach to improve coughing and to explore the establishment of criteria for the use of gastrostomy based on cough and respiratory dysfunctions. Eighteen probable MSA patients participated in the study. They were categorized into air stacking and non-air stacking groups. First, we investigated how the inspiration volume changes by applying maximum insufflation capacity (MIC). Second, peak cough flow (PCF) was measured by different cough augmentation methods: 1) spontaneous coughing (SpC); 2) SpC with MIC (SpC + MIC); 3) SpC with manually assisted cough (MAC) (SpC + MAC); and 4) SpC with MIC and MAC (SpC + MIC + MAC). Among these four conditions, PCF values were compared to determine the most effective approach for cough augmentation. Receiver operating characteristic analysis was performed on percent forced vital capacity (%FVC) to determine an index for discriminating PCF below160 L/min, which indicates a high risk of suffocation, involving SpC and SpC + MIC. Inspiration volume increased significantly with MIC in both groups (P < 0.05), and PCF increased significantly with MIC in the air stacking group (P < 0.01). PCF could not be maintained at 160 L/min when %FVC fell below 59%, even when MIC was applied. PCF increases with MIC in patients with MSA. It may be meaningful to consider the timing of gastrostomy introduction based on the severity of cough and respiratory dysfunction.

Lung Insufflation Capacity with a New Device in Amyotrophic Lateral Sclerosis: Measurement of the Lung Volume Recruitment in Respiratory Therapy

ABSTRACTObjective:The aim of this study was to validate the usefulness of the measurement of lung insufflation capacity (LIC) using the LIC TRAINER (LT) in patients with amyotrophic lateral sclerosis (ALS). Methods:This retrospective study was conducted in the rehabilitation departments of the Japanese National Center of Neurology and Psychiatry and involved 20 ALS patients who underwent respiratory therapy between April 1, 2014, and December 2017. The vital capacity (VC), maximum insufflation capacity (MIC), and LIC measurements at the start of respiratory therapy were extracted from the medical records, and patients were divided into three groups: group A, VC could not be measured; group B, VC could be measured, but MIC was less than VC; and group C, MIC was larger than VC. LIC could be measured in all groups. In group C, paired t-tests were used to analyze whether there was a significant difference in the volumes measured using different methods. Results:LIC was 950, 1863±595, and 2980±1176 ml in groups A (n=1), B (n=10), and C (n=9), respectively. In groups A and B, LIC could be measured in all patients, even when VC or MIC could not be measured. In group C, the measured LIC value was significantly greater than MIC (p=0.003). Conclusion:LIC could be successfully measured using the LT. By using the LT, it was feasible to conveniently perform LIC measurements, suggesting that it could be a useful device for performing respiratory therapy in ALS patients.

Active lung volume recruitment to preserve vital capacity in Duchenne muscular dystrophy.

To consider the effect of active lung volume recruitment ("air stacking") on rate of decline in vital capacity. Retrospective cross-sectional design. People with Duchenne muscular dystrophy. Vital capacity was measured at every patient visit and then graphed. Air stacking using volume-preset ventilation or manual resuscitator bag was introduced to all patients after their vital capacity plateaued (reached a lifetime maximum). For 151 consecutive patients with multi-year data, the 1-year rate of greatest decline in post-plateau vital capacity was 104 ml (8.8%)/year and occurred from age 20 to 21 years. For 53 patients with multi-visit data for whom air stacking was begun at the immediate post-plateau visit, the 1-year rate of greatest decline in vital capacity was 118 ml (8.5%) and occurred from age 20 to 21 years. Between annual visits, vital capacity and maximum insufflation capacity increased 26.4% and 43.3% of the time, respectively. The peak of maximal vital capacity decline occurred more than 5 years later than previously reported without air stacking. For patients with Duchenne muscular dystrophy, active lung volume recruitment may help to preserve vital capacity. Effects on post-plateau vital capacity may be a useful outcome measure for therapeutic trials.

Acute Effects of Air Stacking Versus Glossopharyngeal Breathing in Patients with Neuromuscular Disease

Objective: To compare the effects of Air Stacking (AS) and Glossopharyngeal Breathing (GPB) on the Maximum Insufflation Capacity (MIC) in patients with Neuromuscular Disease (NMD). Methods: We design a randomized cross-over study. Children and adolescents with NMD who were users of non-invasive mechanical ventilation were recruited. Vital capacity (VC) and MIC were measured before and after the intervention with AS and GPB. Values were compared pre- and postintervention and were considered statistically significant if p <0.05. Results: We selected 14 patients with a median age of 12.5 years (range 9-18) with the following diagnoses: Duchenne Muscular Dystrophy (7), Spinal Muscular Atrophy Type II (3), Spinal Cord

A Comparison of Cough Assistance Techniques in Patients with Respiratory Muscle Weakness.

PurposeTo assess the ability of a mechanical in-exsufflator (MI-E), either alone or in combination with manual thrust, to augment cough in patients with neuromuscular disease (NMD) and respiratory muscle dysfunction.Materials and MethodsFor this randomized crossover single-center controlled trial, patients with noninvasive ventilator-dependent NMD were recruited. The primary outcome was peak cough flow (PCF), which was measured in each patient after a cough that was unassisted, manually assisted following a maximum insufflation capacity (MIC) maneuver, assisted by MI-E, or assisted by manual thrust plus MI-E. The cough augmentation techniques were provided in random order. PCF was measured using a new device, the Cough Aid.ResultsAll 40 enrolled participants (37 males, three females; average age, 20.9±7.2 years) completed the study. The mean (standard deviation) PCFs in the unassisted, manually assisted following an MIC maneuver, MI-E-assisted, and manual thrust plus MI-E-assisted conditions were 95.7 (40.5), 155.9 (53.1), 177.2 (33.9), and 202.4 (46.6) L/min, respectively. All three interventions significantly improved PCF. However, manual assistance following an MIC maneuver was significantly less effective than MI-E alone. Manual thrust plus MI-E was significantly more effective than both of these interventions.ConclusionIn patients with NMD and respiratory muscle dysfunction, MI-E alone was more effective than manual assistance following an MIC maneuver. However, MI-E used in conjunction with manual thrust improved PCF even further.

Adaptation and serviceability of the maximum insufflation capacity (MIC) training to the patients with amyotrophic lateral sclerosis

Adaptation and serviceability of the maximum insufflation capacity (MIC) training to the patients with amyotrophic lateral sclerosis

Optimum insufflation capacity and peak cough flow in neuromuscular disorders.

For patients with neuromuscular disorders, lung insufflation with positive pressure is an accepted technique to increase inspiratory volume over VC to improve peak cough flow (PCF). The aim of the study was to determine the pressure or volume required to achieve the highest individual PCF. In 40 patients dependent on noninvasive ventilation (VC, 16 ± 11% predicted; age, 20 ± 4 yr) and in 20 healthy control subjects, insufflation capacity (IC) was measured during titration from 10 to maximum 40 mbar using intermittent positive pressure breathing (IPPB) or the lung insufflation assist maneuver (LIAM) of the VENTIlogic LS ventilator. IPPB or LIAM titration resulted in a pressure-volume curve with an estimated total compliance of 0.23 ± 0.11 L/kPa in the patients and 1.0 ± 0.3 L/kPa in the controls and a plateau for IC at pressures between 30 and 40 mbar. IPPB or LIAM improved VC from 451 ± 229 ml to a maximum IC (ICmax) of 1,027 ± 329 ml, and PCF improved from 109 ± 45 to 202 ± 62 L/min (P < 0.01 for all). The highest individual PCF was achieved with 27 ± 6 mbar and an IC of 924 ± 379 ml, which was significantly below ICmax (P < 0.01). A submaximal insufflation is ideal for generating the best individual PCF even in patients with severely reduced compliance of the respiratory system. Optimum insufflation capacity can be achieved using IPPB or LIAM with moderate pressures. Both techniques are equally effective and considered safe.

A Study of valproic acid for patients with spinal muscular atrophy

AbstractBackgroundValproic acid (VPA) is expected to become an effective therapeutic agent for spinal muscular atrophy (SMA) because of its histone deacetylase inhibitor effect.AimTo evaluate the effectiveness of VPA for SMA.MethodsSeven consecutive Japanese SMA patients (three males, four females) were recruited. Of those, six were type 2 (cases A–E, G) and one was type 3 (case F). One female patient (case E) was aged 2 years and 10 months, whereas the others ranged in age from 15 to 42 years. VPA was administered for 6 months with L‐carnitine. We carried out SMN transcript analysis of peripheral white blood cells, and evaluated using the Modified Hammersmith Functional Motor Scale for SMA (MHFMS), vital capacity (VC), maximum insufflation capacity (MIC), and cough peak flow (CPF) before and at 1, 3 and 6 months after starting treatment.ResultsCases B–E and G completed the study. The final VPA dosage in cases B–D and G was 400 mg/day, whereas that in case E was 100 mg/day. The quantity of the FL‐SMN transcription product showed a tendency to increase. Case E showed a remarkable improvement in MHFMS, and gained motor function to turn from side to side during the study period. Although no significant changes were observed in MHFMS in the older cases, VC, MIC and CPF were improved in those.ConclusionOur findings suggest that VPA treatment is effective for improving MHFMS and respiratory function in some SMA patients. A placebo‐controlled randomized trial is warranted to confirm the efficacy of VPA for SMA.

Predictors of need for noninvasive ventilation during respiratory tract infections in medically stable, non-ventilated subjects with amyotrophic lateral sclerosis.

Acute lower respiratory infections can impair muscle strength in patients with amyotrophic lateral sclerosis (ALS). When associated with an increase in load on the respiratory system, this situation may precipitate hypercapnic respiratory failure in non-ventilated patients with ALS. The aim of this study was to determine whether a clinical or functional parameter can predict the need for noninvasive ventilation (NIV) during an acute respiratory infection for medically stable, non-ventilated patients with ALS. This was a prospective study involving all non-ventilated subjects with ALS admitted due to an acute respiratory infection to a respiratory care unit from a tertiary hospital. Thirty-two non-ventilated subjects with ALS were admitted to our respiratory care unit due to an acute respiratory infection: 60.72 ± 10.54 y, 13 males, 23 with spinal onset, FVC of 1.58 ± 0.83 L, FVC of 56.21 ± 23.15% of predicted, peak cough flow of 3.41 ± 1.77 L/s, maximum insufflation capacity of 1.87 ± 0.94 L, revised Amyotrophic Lateral Sclerosis Functional Rating Scale score of 22.80 ± 8.83, and Norris bulbar score of 23.48 ± 12.14. Fifteen subjects required NIV during the episode. Logistic regression analysis showed that the only predictors of need for NIV were percent-of-predicted FVC (odds ratio of 1.06, 95% CI 1.01-1.11, P = .02) and peak cough flow (odds ratio of 2.57, 95% CI 1.18-5.59, P = .02). In medically stable, non-ventilated patients with ALS, measurement of percent-of-predicted FVC and peak cough flow can predict the need for NIV during an acute lower respiratory tract infection.

Air stacking: effects on pulmonary function in patients with spinal muscular atrophy and in patients with congenital muscular dystrophy.

OBJECTIVE: Respiratory complications are the main causes of morbidity and mortality in patients with neuromuscular disease (NMD). The objectives of this study were to determine the effects that routine daily home air-stacking maneuvers have on pulmonary function in patients with spinal muscular atrophy (SMA) and in patients with congenital muscular dystrophy (CMD), as well as to identify associations between spinal deformities and the effects of the maneuvers. METHODS: Eighteen NMD patients (ten with CMD and eight with SMA) were submitted to routine daily air-stacking maneuvers at home with manual resuscitators for four to six months, undergoing pulmonary function tests before and after that period. The pulmonary function tests included measurements of FVC; PEF; maximum insufflation capacity (MIC); and assisted and unassisted peak cough flow (APCF and UPCF, respectively) with insufflations. RESULTS: After the use of home air-stacking maneuvers, there were improvements in the APCF and UPCF. In the patients without scoliosis, there was also a significant increase in FVC. When comparing patients with and without scoliosis, the increases in APCF and UPCF were more pronounced in those without scoliosis. CONCLUSIONS: Routine daily air-stacking maneuvers with a manual resuscitator appear to increase UPCF and APCF in patients with NMD, especially in those without scoliosis.

Pneumothorax as a complication of lung volume recruitment

Lung volume recruitment involves deep inflation techniques to achieve maximum insufflation capacity in patients with respiratory muscle weakness, in order to increase peak cough flow, thus helping to maintain airway patency and improve ventilation. One of these techniques is air stacking, in which a manual resuscitator is used in order to inflate the lungs. Although intrathoracic pressures can rise considerably, there have been no reports of respiratory complications due to air stacking. However, reaching maximum insufflation capacity is not recommended in patients with known structural abnormalities of the lungs or chronic obstructive airway disease. We report the case of a 72-year-old woman who had poliomyelitis as a child, developed torsion scoliosis and post-polio syndrome, and had periodic but infrequent asthma attacks. After performing air stacking for 3 years, the patient suddenly developed a pneumothorax, indicating that this technique should be used with caution or not at all in patients with a known pulmonary pathology

Lung Volume Recruitment Slows Pulmonary Function Decline in Duchenne Muscular Dystrophy

McKim DA, Katz SL, Barrowman N, Ni A, LeBlanc C. Lung volume recruitment slows pulmonary function decline in Duchenne muscular dystrophy. ObjectiveTo evaluate the long-term effect on measures of forced vital capacity (FVC) before and after the introduction of regular lung volume recruitment (LVR) maneuvers (breath-stacking) in individuals with Duchenne muscular dystrophy (DMD). DesignRetrospective cohort study of pulmonary function data, including FVC, cough peak flow (CPF), maximum inspiratory pressure (MIP), and maximum expiratory pressure (MEP). Data were collected for 33 months prior to and 45 months after LVR introduction. SettingAmbulatory care in a tertiary level regional rehabilitation center in Canada. ParticipantsAll individuals (N=22) with DMD (mean age ± SD, 19.6±2.4y), who were prescribed LVR and reported adherence with therapy. InterventionsIntroduction of regular LVR (breath-stacking); 3 to 5 maximal lung inflations (maximum insufflation capacity [MIC]) using a hand-held resuscitation bag and mouthpiece, twice daily. Main Outcome MeasuresMeasures included the rate of decline of FVC in percent-predicted, before and after the introduction of regular LVR. Changes in maximum pressures (MIP, MEP), MIC, and cough peak flows were also measured. ResultsAt LVR initiation, FVC was 21.8±16.9 percent-predicted, and cough peak flows were <270L/min (144.8±106.9L/min). Annual decline of FVC was 4.7 percent-predicted a year before LVR and 0.5 percent-predicted a year after LVR initiation. The difference, 4.2 percent-predicted a year (95% confidence interval, 3.5–4.9; P<.000), represents an 89% improvement in the annual rate of FVC decline. ConclusionsThe rate of FVC decline in DMD patients improves dramatically with initiation of regular LVR.

The Effect of Position on Measured Lung Capacity of Patients with Spinal Cord Injury

[Purpose] To determine whether position affects measured lung capacity of spinal cord injury patients. [Subjects] The study subjects were 45 patients with spinal cord injury (cervical level 15, thoracic level 15, lumbar level 15). Subjects were provided with a full explanation of the experimental procedures and all provided written consent signifying their voluntary participation. [Methods] We used a spirometer (Spirometer, Micromedical Ltd, UK) to measure pulmonary function in the supine and sitting positions (straightened upper body at an angle of 90°). Forced vital capacity (FVC), forced expiratory volume during the first second (FEV1), tidal volume (TV), and maximum insufflation capacity (MIC) were also measured. [Results] FVC, FEV1, TV, MIC (%) were greater in the supine than in the sitting position for those with injury at the cervical or thoracic injury level. On the other hand, FVC, FEV1, TV, MIC (%) were lower in the supine position for those with an injury at the lumbar level. [Conclusion] More attention should be paid to the effect of injury level on measured lung capacity.

Lung Inflation Training Using a Positive End-expiratory Pressure Valve in Neuromuscular Disorders

Respiratory muscle weakness causes alveolar hypoventilation and reduced lung compliance in neuromuscular disorders. Lung inflation is important to prevent secondary pulmonary complications however respiratory and laryngeal dysfunction often hamper lung inflation. There is a need for a convenient and low-cost device that enables effective lung inflation. We tested a lung inflation training method using a positive end-expiratory pressure (PEEP) valve. Vital capacity (VC), maximum insufflation capacity (MIC) and peak cough flow (PCF) as well as PEEP lung inflation capacity (PIC) were assessed in 93 neuromuscular patients. Consecutive PIC training was done for 4 months in six tracheostomized Duchenne muscular dystrophy (DMD) patients and PIC was assessed before and after training. PIC training was practicable in all participants and no serious adverse events were detected. PIC was significantly higher than VC or MIC in all disorders, although MIC was higher than VC in DMD only. Patients with dysphagia showed lower MIC and PCF compared with non dysphagic patients. PIC was as low as 345±77 mL in tracheostomized DMD patients; however consecutive training increased it up to 619±205 mL. The PEEP valve enabled effective lung inflation regardless of laryngeal function. Consecutive training can improve lung condition even in advanced cases. Early introduction of PIC training could be effective at preventing respiratory complications in patients with neuromuscular disorders.

Duchenne Muscular Dystrophy: Continuous Noninvasive Ventilatory Support Prolongs Survival

To describe survival outcomes with noninvasive ventilation (NIV) for full ventilatory support, and a mechanically assisted cough and oximetry protocol in a series of patients with Duchenne muscular dystrophy. We monitored end-tidal carbon dioxide (P(ETCO(2))), S(pO(2)), vital capacity, maximum insufflation capacity, and cough peak flow. Nocturnal NIV was initiated for symptomatic hypoventilation. An oximeter and mechanically assisted cough device were prescribed when the patient's maximum assisted cough peak flow fell below 300 L/min. Patients used up to continuous NIV and mechanically assisted cough to return S(pO(2)) to ≥ 95% during intercurrent respiratory infections or as otherwise needed. We recorded respiratory and cardiac hospitalizations and mortality, and quantified survival by duration of continuous NIV dependence (ie, unable to maintain oxygenation without the ventilator). With advancing Duchenne muscular dystrophy, 101 nocturnal-only NIV users extended their NIV use throughout the daytime hours and required it continuously for 7.4 ± 6.1 years to 30.1 ± 6.1 years of age, with 56 patients still alive. Twenty-six of the 101 became continuously dependent without requiring hospitalization. Eight tracheostomized users were decannulated to NIV. Thirty-one consecutive unweanable intubated patients were extubated to NIV plus mechanically assisted cough. Of the 67 deaths (including 8 patients who died from heart failure before requiring ventilator use), 34 (52%) were probably cardiac, 14 (21%) were probably respiratory, and 19 (27%) were of unknown or other etiology. Continuous NIV along with mechanically assisted cough and oximetry as needed can prolong life and obviate tracheotomy in patients with Duchenne muscular dystrophy. Unweanable patients can be decannulated and extubated to NIV plus mechanically assisted cough.

Artificial External Glottic Device for Passive Lung Insufflation

PurposeFor patients with neuromuscular disease, air stacking, which inflates the lungs to deep volumes, is important for many reasons. However, neuromuscular patients with severe glottic dysfunction or indwelling tracheostomy tubes cannot air stack effectively. For these patients, we developed a device that permits deep lung insufflations substituting for glottic function.Materials and MethodsThirty-seven patients with bulbar-innervated muscle weakness and/or tracheostomies were recruited. Twenty-three had amyotrophic lateral sclerosis, and 14 were tetraplegic patients due to cervical spinal cord injury. An artificial external glottic device (AEGD) was used to permit passive deep lung insufflation. In order to confirm the utility of AEGD, vital capacity, maximum insufflation capacity (MIC), and lung insufflation capacity (LIC) with AEGD (LICA) were measured.ResultsFor 30 patients, MICs were initially zero. However, with the use of the AEGD, LICA was measurable for all patients. The mean LICA was 1,622.7±526.8 mL. Although MIC was measurable for the remaining 7 patients without utilizing the AEGD, it was significantly less than LICA, which was 1,084.3±259.9 mL and 1,862.9±248 mL, respectively (p<0.05).ConclusionThe AEGD permits lung insufflation by providing deeper lung volumes than possible by air stacking.

Prolonging Survival in Amyotrophic Lateral Sclerosis

To assess the efficacy of noninvasive ventilatory support and intermittent positive pressure ventilation via uncuffed tracheostomy tubes (uTIPPV) to prolong survival in amyotrophic lateral sclerosis. Survival was prolonged by continuous noninvasive ventilatory support or TIPPV dependence. Once noninvasive ventilatory support was no longer adequate for six noninvasive ventilatory support users, they and 22 others underwent tracheotomy within 1 mo of measurement of spirometry (forced vital capacity and forced volume expired in 1 sec), peak cough flows, maximum insufflation capacity, manually assisted peak cough flows, and mechanically assisted peak cough flows. Glottic function was estimated by maximum insufflation capacity, FVC difference, and bulbar-innervated muscle function by Norris scale bulbar-innervated muscle subscore. Cuffless tubes were replaced by cuffed ones when hypoventilation developed despite increasing uTIPPV volumes. The survival of 22 patients was prolonged by continuous noninvasive ventilatory support dependence for 7.8 +/- 8.1 mos (range, 1-36 mos; median, 5 mos) after 13.9 +/- 11.2 mos (range, 2-36 mos) of part-time noninvasive ventilatory support. Six of these and 22 others underwent tracheotomy and initially used uTIPPV effectively. For ten of the 28 (35.7%) patients, the tubes had to be replaced by cuffed ones after 5.7 +/- 7.8 mos with the other 18 still using tracheostomy intermittent positive pressure ventilation volumes via uncuffed tubes for 20.2 +/- 17.6 mos at data collection. Pretracheotomy FVC was significantly lower in the ten patients who eventually required cuffed tubes (0.70 +/- 0.44 vs. 1.06 +/- 0.43 L, P < 0.05). The bulbar-innervated muscle was significantly lower when the uTIPPV users required cuffed TIPPV than when beginning uTIPPV (Norris scale bulbar-innervated muscle subscore, 3.20 +/- 1.30 vs. 8.00 +/- 3.20, P < 0.05), respectively. Noninvasive and tracheostomy IPPV via cuffless tubes can prolong survival for patients with amyotrophic lateral sclerosis until excessive air leak and hypoventilation necessitate a cuffed tube.

Lung Insufflation Capacity in Neuromuscular Disease

To compare maximal passive lung insufflation capacity (LIC) with lung inflation by air stacking (to maximum insufflation capacity [MIC]) and with vital capacity (VC); to explore relationships between these variables that correlate with glottic function and cough peak flows (CPF); to demonstrate the effect of routine inflation therapy on LIC and MIC; and to determine the relative importance of lung inflation therapy as a function of disease severity. Case series of 282 consecutive neuromuscular disease (NMD) clinic patients 7 yrs and older with VC <70% of the predicted normal value. All cooperative patients meeting these criteria were prescribed thrice-daily air stacking and/or maximal passive lung insufflation to pressures of 40-80 cm H2O, and they underwent measurements of VC, MIC, LIC, and unassisted and assisted CPF on every visit. Means +/- standard deviations for VC, MIC, and LIC were 1131 +/- 744, 1712 +/- 926, and 2069 +/- 867 ml, respectively, and, for unassisted and assisted CPF, they were 2.5 +/- 2.0 and 4.3 +/- 2.2 liters/sec, respectively, with all differences statistically significant (P < 0.001). MIC minus VC correlated inversely with LIC minus MIC (P = 0.01) and, therefore, with glottic function. Both MIC and LIC increased with practice (P < 0.001). Increases in LIC but not MIC over VC were greatest for patients with the lowest VC (P < 0.05). There were no complications of lung mobilization therapy. Passive lung insufflation can distend the lungs of patients with NMD significantly greater than air stacking, particularly when glottic and bulbar-innervated muscle dysfunction is severe. LIC, MIC, and VC measurements permit quantifiable assessment of glottic integrity and, therefore, bulbar-innervated muscle function for patients with NMD. The patients who benefit the most from insufflation therapy are those who have the lowest VC.

Long-Term Ventilation for High-Level Tetraplegia: A Report of 2 Cases of Noninvasive Positive-Pressure Ventilation

Toki A, Tamura R, Sumida M. Long-term ventilation for high-level tetraplegia: a report of 2 cases of noninvasive positive-pressure ventilation. Ventilator-dependent patients with tetraplegia rarely use noninvasive positive-pressure ventilation (NPPV) for long-term ventilation. We report 2 patients with high-level traumatic tetraplegia who were able to return home after being changed from traditional ventilation to NPPV. When they were referred to our hospital from acute care hospitals 2 to 6 months after injury, both were on tracheostomy ventilation with a cuff inflated 24 hours a day, and tidal volume (V t) settings were low. In case 1, a man with complete C1 tetraplegia was admitted to our hospital 6 months after injury. We changed ventilator settings to high V t and introduced NPPV. He was discharged home with NPPV with a volume-setting ventilator. Case 2 involved a man in his late twenties with complete C1 tetraplegia who was discharged home with NPPV. After discharge, he trained in glossopharyngeal breathing by himself, enabling him to breathe up to 1900mL of maximum insufflation capacity. Both have lived nearly 1 year without pulmonary complications in the community. They use visiting nurses 3 times a week and services of visiting caregivers. Further study is needed to determine the usefulness of NPPV for long-term ventilatory management.